642259638 has 16 divisors (see below), whose sum is σ = 1427243760. Its totient is φ = 214086528.

The previous prime is 642259637. The next prime is 642259649. The reversal of 642259638 is 836952246.

642259638 is a `hidden beast` number, since 6 + 4 + 2 + 2 + 5 + 9 + 638 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 642259593 and 642259602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642259637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5946795 + ... + 5946902.

It is an arithmetic number, because the mean of its divisors is an integer number (89202735).

Almost surely, 2^642259638 is an apocalyptic number.

642259638 is an abundant number, since it is smaller than the sum of its proper divisors (784984122).

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

642259638 is a wasteful number, since it uses less digits than its factorization.

642259638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11893708 (or 11893702 counting only the distinct ones).

The product of its digits is 622080, while the sum is 45.

The square root of 642259638 is about 25342.8419479742. The cubic root of 642259638 is about 862.7869019079.

The spelling of 642259638 in words is "six hundred forty-two million, two hundred fifty-nine thousand, six hundred thirty-eight".