691831221020 has 24 divisors (see below), whose sum is σ = 1488280823568. Its totient is φ = 269982915200.

The previous prime is 691831220989. The next prime is 691831221049. The reversal of 691831221020 is 20122138196.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 421847486 + ... + 421849125.

It is an arithmetic number, because the mean of its divisors is an integer number (62011700982).

Almost surely, 2^691831221020 is an apocalyptic number.

It is an amenable number.

691831221020 is an abundant number, since it is smaller than the sum of its proper divisors (796449602548).

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

691831221020 is a wasteful number, since it uses less digits than its factorization.

691831221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 843696661 (or 843696659 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 35.

The spelling of 691831221020 in words is "six hundred ninety-one billion, eight hundred thirty-one million, two hundred twenty-one thousand, twenty".