61505664 has 64 divisors (see below), whose sum is σ = 178238880. Its totient is φ = 18636800.

The previous prime is 61505659. The next prime is 61505701. The reversal of 61505664 is 46650516.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-3 number, since 3×61505664³ (a number of 24 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

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, 3057 + ... + 11504.

Almost surely, 2^61505664 is an apocalyptic number.

61505664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

61505664 is an abundant number, since it is smaller than the sum of its proper divisors (116733216).

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

61505664 is a wasteful number, since it uses less digits than its factorization.

61505664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14589 (or 14577 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 33.

The square root of 61505664 is about 7842.5546858151. The cubic root of 61505664 is about 394.7344559313.

The spelling of 61505664 in words is "sixty-one million, five hundred five thousand, six hundred sixty-four".