815567644640 has 96 divisors (see below), whose sum is σ = 2222612711424. Its totient is φ = 277009850880.

The previous prime is 815567644631. The next prime is 815567644657. The reversal of 815567644640 is 46446765518.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (56).

It is a congruent number.

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, 3282896 + ... + 3522575.

It is an arithmetic number, because the mean of its divisors is an integer number (23152215744).

Almost surely, 2^815567644640 is an apocalyptic number.

815567644640 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

815567644640 is an abundant number, since it is smaller than the sum of its proper divisors (1407045066784).

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

815567644640 is a wasteful number, since it uses less digits than its factorization.

815567644640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6805600 (or 6805592 counting only the distinct ones).

The product of its (nonzero) digits is 19353600, while the sum is 56.

The spelling of 815567644640 in words is "eight hundred fifteen billion, five hundred sixty-seven million, six hundred forty-four thousand, six hundred forty".