691680384 has 80 divisors (see below), whose sum is σ = 2058460470. Its totient is φ = 230556672.

The previous prime is 691680349. The next prime is 691680487. The reversal of 691680384 is 483086196.

It can be written as a sum of positive squares in only one way, i.e., 482241600 + 209438784 = 21960^2 + 14472^2 .

It is a super-2 number, since 2×691680384² = 956843507220774912, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 22989 + ... + 43724.

Almost surely, 2^691680384 is an apocalyptic number.

691680384 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

691680384 is an abundant number, since it is smaller than the sum of its proper divisors (1366780086).

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

691680384 is an equidigital number, since it uses as much as digits as its factorization.

691680384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66739 (or 66718 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 691680384 is about 26299.8171856764. The cubic root of 691680384 is about 884.3723443905.

The spelling of 691680384 in words is "six hundred ninety-one million, six hundred eighty thousand, three hundred eighty-four".