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640927144 = 2311132919319
BaseRepresentation
bin100110001100111…
…100010110101000
31122200000110202101
4212030330112220
52303034132034
6143333143144
721611535154
oct4614742650
91580013671
10640927144
112a9872060
1215a78aab4
13a2a28440
146119c064
153b404514
hex2633c5a8

640927144 has 64 divisors (see below), whose sum is σ = 1460592000. Its totient is φ = 259633920.

The previous prime is 640927141. The next prime is 640927151. The reversal of 640927144 is 441729046.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (640927141) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23517 + ... + 42835.

It is an arithmetic number, because the mean of its divisors is an integer number (22821750).

Almost surely, 2640927144 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640927144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (730296000).

640927144 is an abundant number, since it is smaller than the sum of its proper divisors (819664856).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640927144 is a wasteful number, since it uses less digits than its factorization.

640927144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19378 (or 19374 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 640927144 is about 25316.5389419644. The cubic root of 640927144 is about 862.1898150582.

The spelling of 640927144 in words is "six hundred forty million, nine hundred twenty-seven thousand, one hundred forty-four".

Divisors: 1 2 4 8 11 13 22 26 29 44 52 58 88 104 116 143 232 286 319 377 572 638 754 1144 1276 1508 2552 3016 4147 8294 16588 19319 33176 38638 77276 154552 212509 251147 425018 502294 560251 850036 1004588 1120502 1700072 2009176 2241004 2762617 4482008 5525234 6162761 7283263 11050468 12325522 14566526 22100936 24651044 29133052 49302088 58266104 80115893 160231786 320463572 640927144