642797990 has 16 divisors (see below), whose sum is σ = 1158520752. Its totient is φ = 256789344.

The previous prime is 642797983. The next prime is 642798007. The reversal of 642797990 is 99797246.

It is a happy number.

It is a congruent number.

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, 32969 + ... + 48708.

It is an arithmetic number, because the mean of its divisors is an integer number (72407547).

Almost surely, 2^642797990 is an apocalyptic number.

642797990 is a deficient number, since it is larger than the sum of its proper divisors (515722762).

642797990 is a wasteful number, since it uses less digits than its factorization.

642797990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82471.

The product of its (nonzero) digits is 1714608, while the sum is 53.

The square root of 642797990 is about 25353.4611049458. The cubic root of 642797990 is about 863.0279017093.

The spelling of 642797990 in words is "six hundred forty-two million, seven hundred ninety-seven thousand, nine hundred ninety".