691667979920 has 160 divisors (see below), whose sum is σ = 1768451097600. Its totient is φ = 250444431360.

The previous prime is 691667979917. The next prime is 691667979949. The reversal of 691667979920 is 29979766196.

It is a super-2 number, since 2×691667979920² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6821756 + ... + 6922404.

It is an arithmetic number, because the mean of its divisors is an integer number (11052819360).

Almost surely, 2^691667979920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691667979920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (884225548800).

691667979920 is an abundant number, since it is smaller than the sum of its proper divisors (1076783117680).

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

691667979920 is a wasteful number, since it uses less digits than its factorization.

691667979920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100873 (or 100867 counting only the distinct ones).

The product of its (nonzero) digits is 138883248, while the sum is 71.

The spelling of 691667979920 in words is "six hundred ninety-one billion, six hundred sixty-seven million, nine hundred seventy-nine thousand, nine hundred twenty".