656491938820 has 12 divisors (see below), whose sum is σ = 1378633071564. Its totient is φ = 262596775520.

The previous prime is 656491938799. The next prime is 656491938847. The reversal of 656491938820 is 28839194656.

It can be written as a sum of positive squares in 2 ways, for example, as 479176835076 + 177315103744 = 692226^2 + 421088^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16412298451 + ... + 16412298490.

It is an arithmetic number, because the mean of its divisors is an integer number (114886089297).

Almost surely, 2^656491938820 is an apocalyptic number.

It is an amenable number.

656491938820 is an abundant number, since it is smaller than the sum of its proper divisors (722141132744).

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

656491938820 is a wasteful number, since it uses less digits than its factorization.

656491938820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32824596950 (or 32824596948 counting only the distinct ones).

The product of its (nonzero) digits is 22394880, while the sum is 61.

The spelling of 656491938820 in words is "six hundred fifty-six billion, four hundred ninety-one million, nine hundred thirty-eight thousand, eight hundred twenty".