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642452981 = 4326356809
BaseRepresentation
bin100110010010110…
…000110111110101
31122202212222210212
4212102300313311
52303431443411
6143425555205
721630521522
oct4622606765
91582788725
10642452981
112aa714485
1215b1a5b05
13a3140ac1
1461478149
153b60668b
hex264b0df5

642452981 has 8 divisors (see below), whose sum is σ = 659904960. Its totient is φ = 625115232.

The previous prime is 642452971. The next prime is 642452989. The reversal of 642452981 is 189254246.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2k-642452981 is a prime.

It is a super-2 number, since 2×6424529812 = 825491665591572722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642452989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17096 + ... + 39713.

It is an arithmetic number, because the mean of its divisors is an integer number (82488120).

Almost surely, 2642452981 is an apocalyptic number.

It is an amenable number.

642452981 is a deficient number, since it is larger than the sum of its proper divisors (17451979).

642452981 is a wasteful number, since it uses less digits than its factorization.

642452981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57115.

The product of its digits is 138240, while the sum is 41.

The square root of 642452981 is about 25346.6562094490. The cubic root of 642452981 is about 862.8734697391.

The spelling of 642452981 in words is "six hundred forty-two million, four hundred fifty-two thousand, nine hundred eighty-one".

Divisors: 1 43 263 11309 56809 2442787 14940767 642452981