642157894820 has 48 divisors (see below), whose sum is σ = 1454153741040. Its totient is φ = 236796051456.

The previous prime is 642157894801. The next prime is 642157894883. The reversal of 642157894820 is 28498751246.

642157894820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 52078891264 + 590079003556 = 228208^2 + 768166^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1405937 + ... + 1805816.

It is an arithmetic number, because the mean of its divisors is an integer number (30294869605).

Almost surely, 2^642157894820 is an apocalyptic number.

It is an amenable number.

642157894820 is an abundant number, since it is smaller than the sum of its proper divisors (811995846220).

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

642157894820 is a wasteful number, since it uses less digits than its factorization.

642157894820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3212544 (or 3212542 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 56.

The spelling of 642157894820 in words is "six hundred forty-two billion, one hundred fifty-seven million, eight hundred ninety-four thousand, eight hundred twenty".