61666604516720 has 40 divisors (see below), whose sum is σ = 163856977717344. Its totient is φ = 21142835834112.

The previous prime is 61666604516707. The next prime is 61666604516731. The reversal of 61666604516720 is 2761540666616.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×61666604516720² (a number of 28 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (56).

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, 55059467759 + ... + 55059468878.

Almost surely, 2^{61666604516720} is an apocalyptic number.

It is an amenable number.

61666604516720 is an abundant number, since it is smaller than the sum of its proper divisors (102190373200624).

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

61666604516720 is a wasteful number, since it uses less digits than its factorization.

61666604516720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110118936657 (or 110118936651 counting only the distinct ones).

The product of its (nonzero) digits is 13063680, while the sum is 56.

The spelling of 61666604516720 in words is "sixty-one trillion, six hundred sixty-six billion, six hundred four million, five hundred sixteen thousand, seven hundred twenty".