642403656 has 32 divisors (see below), whose sum is σ = 1784455200. Its totient is φ = 214134480.

The previous prime is 642403631. The next prime is 642403673. The reversal of 642403656 is 656304246.

642403656 is a `hidden beast` number, since 642 + 4 + 0 + 3 + 6 + 5 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 642403656.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1486830 + ... + 1487261.

It is an arithmetic number, because the mean of its divisors is an integer number (55764225).

Almost surely, 2^642403656 is an apocalyptic number.

It is an amenable number.

642403656 is an abundant number, since it is smaller than the sum of its proper divisors (1142051544).

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

642403656 is a wasteful number, since it uses less digits than its factorization.

642403656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2974106 (or 2974096 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 642403656 is about 25345.6831827434. The cubic root of 642403656 is about 862.8513865027.

It can be divided in two parts, 64240 and 3656, that added together give a triangular number (67896 = T₃₆₈).

The spelling of 642403656 in words is "six hundred forty-two million, four hundred three thousand, six hundred fifty-six".