77809721612 has 48 divisors (see below), whose sum is σ = 157984888320. Its totient is φ = 32841177600.

The previous prime is 77809721597. The next prime is 77809721629. The reversal of 77809721612 is 21612790877.

It is a happy number.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors.

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, 1825787 + ... + 1867917.

It is an arithmetic number, because the mean of its divisors is an integer number (3291351840).

Almost surely, 2^77809721612 is an apocalyptic number.

It is an amenable number.

77809721612 is an abundant number, since it is smaller than the sum of its proper divisors (80175166708).

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

77809721612 is a wasteful number, since it uses less digits than its factorization.

77809721612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43142 (or 43140 counting only the distinct ones).

The product of its (nonzero) digits is 592704, while the sum is 50.

The spelling of 77809721612 in words is "seventy-seven billion, eight hundred nine million, seven hundred twenty-one thousand, six hundred twelve".