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642512640 = 28357114153
BaseRepresentation
bin100110010010111…
…111011100000000
31122210000000122110
4212102333130000
52303440401030
6143431135320
721631160460
oct4622773400
91583000573
10642512640
112aa755290
1215b214540
13a3161cc3
1461491ba0
153b6191b0
hex264bf700

642512640 has 576 divisors, whose sum is σ = 2670216192. Its totient is φ = 127795200.

The previous prime is 642512623. The next prime is 642512641. The reversal of 642512640 is 46215246.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 642512598 and 642512607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642512641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12122854 + ... + 12122906.

It is an arithmetic number, because the mean of its divisors is an integer number (4635792).

Almost surely, 2642512640 is an apocalyptic number.

642512640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642512640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1335108096).

642512640 is an abundant number, since it is smaller than the sum of its proper divisors (2027703552).

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

642512640 is a wasteful number, since it uses less digits than its factorization.

642512640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 642512640 is about 25347.8330434773. The cubic root of 642512640 is about 862.9001780879.

Adding to 642512640 its reverse (46215246), we get a palindrome (688727886).

The spelling of 642512640 in words is "six hundred forty-two million, five hundred twelve thousand, six hundred forty".