79621561 has 4 divisors (see below), whose sum is σ = 83083392. Its totient is φ = 76159732.

The previous prime is 79621537. The next prime is 79621573. The reversal of 79621561 is 16512697.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 79621561 - 2⁷ = 79621433 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 79621561.

It is not an unprimeable number, because it can be changed into a prime (79621511) 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, 1730881 + ... + 1730926.

It is an arithmetic number, because the mean of its divisors is an integer number (20770848).

Almost surely, 2^79621561 is an apocalyptic number.

It is an amenable number.

79621561 is a deficient number, since it is larger than the sum of its proper divisors (3461831).

79621561 is a wasteful number, since it uses less digits than its factorization.

79621561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3461830.

The product of its digits is 22680, while the sum is 37.

The square root of 79621561 is about 8923.0914485956. The cubic root of 79621561 is about 430.2064287374.

The spelling of 79621561 in words is "seventy-nine million, six hundred twenty-one thousand, five hundred sixty-one".