61636864 has 18 divisors (see below), whose sum is σ = 123033470. Its totient is φ = 30818304.

The previous prime is 61636859. The next prime is 61636877. The reversal of 61636864 is 46863616.

It can be written as a sum of positive squares in only one way, i.e., 60715264 + 921600 = 7792^2 + 960^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 120129 + ... + 120640.

Almost surely, 2^61636864 is an apocalyptic number.

61636864 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

61636864 is a deficient number, since it is larger than the sum of its proper divisors (61396606).

61636864 is an equidigital number, since it uses as much as digits as its factorization.

61636864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240785 (or 240771 counting only the distinct ones).

The product of its digits is 124416, while the sum is 40.

The square root of 61636864 is about 7850.9148511495. The cubic root of 61636864 is about 395.0149308035.

It can be divided in two parts, 61636 and 864, that added together give a square (62500 = 250²).

The spelling of 61636864 in words is "sixty-one million, six hundred thirty-six thousand, eight hundred sixty-four".