642491538216 has 128 divisors (see below), whose sum is σ = 1837898588160. Its totient is φ = 185401785600.

The previous prime is 642491538211. The next prime is 642491538217. The reversal of 642491538216 is 612835194246.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (642491538211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 240640 + ... + 1158831.

It is an arithmetic number, because the mean of its divisors is an integer number (14358582720).

Almost surely, 2^642491538216 is an apocalyptic number.

642491538216 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

642491538216 is an abundant number, since it is smaller than the sum of its proper divisors (1195407049944).

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

642491538216 is a wasteful number, since it uses less digits than its factorization.

642491538216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1399575 (or 1399571 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 51.

The spelling of 642491538216 in words is "six hundred forty-two billion, four hundred ninety-one million, five hundred thirty-eight thousand, two hundred sixteen".