691979981810 has 32 divisors (see below), whose sum is σ = 1361397143232. Its totient is φ = 251686860480.

The previous prime is 691979981801. The next prime is 691979981837. The reversal of 691979981810 is 18189979196.

It is a super-2 number, since 2×691979981810² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39714596 + ... + 39732015.

It is an arithmetic number, because the mean of its divisors is an integer number (42543660726).

Almost surely, 2^691979981810 is an apocalyptic number.

691979981810 is a deficient number, since it is larger than the sum of its proper divisors (669417161422).

691979981810 is a wasteful number, since it uses less digits than its factorization.

691979981810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79446698.

The product of its (nonzero) digits is 17635968, while the sum is 68.

The spelling of 691979981810 in words is "six hundred ninety-one billion, nine hundred seventy-nine million, nine hundred eighty-one thousand, eight hundred ten".