691131972 has 48 divisors (see below), whose sum is σ = 1627766784. Its totient is φ = 228228000.

The previous prime is 691131971. The next prime is 691131979. The reversal of 691131972 is 279131196.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 691131972.

It is not an unprimeable number, because it can be changed into a prime (691131971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 758197 + ... + 759107.

It is an arithmetic number, because the mean of its divisors is an integer number (33911808).

Almost surely, 2^691131972 is an apocalyptic number.

It is an amenable number.

691131972 is an abundant number, since it is smaller than the sum of its proper divisors (936634812).

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

691131972 is a wasteful number, since it uses less digits than its factorization.

691131972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1440 (or 1438 counting only the distinct ones).

The product of its digits is 20412, while the sum is 39.

The square root of 691131972 is about 26289.3889620889. The cubic root of 691131972 is about 884.1385520907.

It can be divided in two parts, 6911 and 31972, that added together give a palindrome (38883).

The spelling of 691131972 in words is "six hundred ninety-one million, one hundred thirty-one thousand, nine hundred seventy-two".