691412644 has 24 divisors (see below), whose sum is σ = 1379698488. Its totient is φ = 300341760.

The previous prime is 691412639. The next prime is 691412651. The reversal of 691412644 is 446214196.

It can be written as a sum of positive squares in 4 ways, for example, as 19980900 + 671431744 = 4470^2 + 25912^2 .

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 390187 + ... + 391954.

It is an arithmetic number, because the mean of its divisors is an integer number (57487437).

Almost surely, 2^691412644 is an apocalyptic number.

It is an amenable number.

691412644 is a deficient number, since it is larger than the sum of its proper divisors (688285844).

691412644 is a wasteful number, since it uses less digits than its factorization.

691412644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 782175 (or 782173 counting only the distinct ones).

The product of its digits is 41472, while the sum is 37.

The square root of 691412644 is about 26294.7265435486. The cubic root of 691412644 is about 884.2582201914.

The spelling of 691412644 in words is "six hundred ninety-one million, four hundred twelve thousand, six hundred forty-four".