691240064 has 32 divisors (see below), whose sum is σ = 1449562800. Its totient is φ = 327428352.

The previous prime is 691240063. The next prime is 691240079. The reversal of 691240064 is 460042196.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 691240064.

It is not an unprimeable number, because it can be changed into a prime (691240063) 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 3 ways as a sum of consecutive naturals, for example, 139682 + ... + 144545.

Almost surely, 2^691240064 is an apocalyptic number.

691240064 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

691240064 is an abundant number, since it is smaller than the sum of its proper divisors (758322736).

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

691240064 is a wasteful number, since it uses less digits than its factorization.

691240064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284260 (or 284248 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 691240064 is about 26291.4446921427. Note that the first 3 decimals coincide. The cubic root of 691240064 is about 884.1846423341.

The spelling of 691240064 in words is "six hundred ninety-one million, two hundred forty thousand, sixty-four".