61651664 has 20 divisors (see below), whose sum is σ = 120145956. Its totient is φ = 30646272.

The previous prime is 61651649. The next prime is 61651669. The reversal of 61651664 is 46615616.

It can be written as a sum of positive squares in 2 ways, for example, as 22963264 + 38688400 = 4792^2 + 6220^2 .

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61651669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8369 + ... + 13904.

Almost surely, 2^61651664 is an apocalyptic number.

It is an amenable number.

61651664 is a deficient number, since it is larger than the sum of its proper divisors (58494292).

61651664 is a wasteful number, since it uses less digits than its factorization.

61651664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22454 (or 22448 counting only the distinct ones).

The product of its digits is 25920, while the sum is 35.

The square root of 61651664 is about 7851.8573598863. The cubic root of 61651664 is about 395.0465447475.

The spelling of 61651664 in words is "sixty-one million, six hundred fifty-one thousand, six hundred sixty-four".