691591972 has 12 divisors (see below), whose sum is σ = 1227332736. Its totient is φ = 340925480.

The previous prime is 691591969. The next prime is 691591997. The reversal of 691591972 is 279195196.

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, 1217308 + ... + 1217875.

It is an arithmetic number, because the mean of its divisors is an integer number (102277728).

Almost surely, 2^691591972 is an apocalyptic number.

It is an amenable number.

691591972 is a deficient number, since it is larger than the sum of its proper divisors (535740764).

691591972 is a wasteful number, since it uses less digits than its factorization.

691591972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2435258 (or 2435256 counting only the distinct ones).

The product of its digits is 306180, while the sum is 49.

The square root of 691591972 is about 26298.1362837749. The cubic root of 691591972 is about 884.3346620249.

The spelling of 691591972 in words is "six hundred ninety-one million, five hundred ninety-one thousand, nine hundred seventy-two".