61566616651 has 4 divisors (see below), whose sum is σ = 61568229600. Its totient is φ = 61565003704.

The previous prime is 61566616627. The next prime is 61566616691. The reversal of 61566616651 is 15661666516.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61566616651 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61566616595 and 61566616604.

It is not an unprimeable number, because it can be changed into a prime (61566616691) 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, 747796 + ... + 826033.

It is an arithmetic number, because the mean of its divisors is an integer number (15392057400).

Almost surely, 2^61566616651 is an apocalyptic number.

61566616651 is a deficient number, since it is larger than the sum of its proper divisors (1612949).

61566616651 is a wasteful number, since it uses less digits than its factorization.

61566616651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1612948.

The product of its digits is 1166400, while the sum is 49.

The spelling of 61566616651 in words is "sixty-one billion, five hundred sixty-six million, six hundred sixteen thousand, six hundred fifty-one".