642805905900 has 36 divisors (see below), whose sum is σ = 1859851755272. Its totient is φ = 171414908160.

The previous prime is 642805905871. The next prime is 642805905923. The reversal of 642805905900 is 9509508246.

It is a self number, because there is not a number n which added to its sum of digits gives 642805905900.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1071342877 + ... + 1071343476.

Almost surely, 2^642805905900 is an apocalyptic number.

642805905900 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

642805905900 is an abundant number, since it is smaller than the sum of its proper divisors (1217045849372).

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

642805905900 is a wasteful number, since it uses less digits than its factorization.

642805905900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2142686370 (or 2142686363 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 48.

The spelling of 642805905900 in words is "six hundred forty-two billion, eight hundred five million, nine hundred five thousand, nine hundred".