61666656 has 24 divisors (see below), whose sum is σ = 161875224. Its totient is φ = 20555520.

The previous prime is 61666651. The next prime is 61666681. The reversal of 61666656 is 65666616.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61666651) 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, 321085 + ... + 321276.

It is an arithmetic number, because the mean of its divisors is an integer number (6744801).

Almost surely, 2^61666656 is an apocalyptic number.

It is an amenable number.

61666656 is an abundant number, since it is smaller than the sum of its proper divisors (100208568).

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

61666656 is a wasteful number, since it uses less digits than its factorization.

61666656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642374 (or 642366 counting only the distinct ones).

The product of its digits is 233280, while the sum is 42.

The square root of 61666656 is about 7852.8119804310. The cubic root of 61666656 is about 395.0785636605.

The spelling of 61666656 in words is "sixty-one million, six hundred sixty-six thousand, six hundred fifty-six".