78877640646 has 32 divisors (see below), whose sum is σ = 200324167680. Its totient is φ = 22536468648.

The previous prime is 78877640629. The next prime is 78877640659. The reversal of 78877640646 is 64604677887.

It is a super-2 number, since 2×78877640646² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

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, 104335126 + ... + 104335881.

It is an arithmetic number, because the mean of its divisors is an integer number (6260130240).

Almost surely, 2^78877640646 is an apocalyptic number.

78877640646 is an abundant number, since it is smaller than the sum of its proper divisors (121446527034).

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

78877640646 is a wasteful number, since it uses less digits than its factorization.

78877640646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208671025 (or 208671019 counting only the distinct ones).

The product of its (nonzero) digits is 75866112, while the sum is 63.

The spelling of 78877640646 in words is "seventy-eight billion, eight hundred seventy-seven million, six hundred forty thousand, six hundred forty-six".