79720961 has 4 divisors (see below), whose sum is σ = 81027924. Its totient is φ = 78414000.

The previous prime is 79720937. The next prime is 79720969. The reversal of 79720961 is 16902797.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11971600 + 67749361 = 3460^2 + 8231^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-79720961 is a prime.

It is a super-4 number, since 4×79720961⁴ (a number of 33 digits) contains 4444 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79720969) 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, 653390 + ... + 653511.

It is an arithmetic number, because the mean of its divisors is an integer number (20256981).

Almost surely, 2^79720961 is an apocalyptic number.

It is an amenable number.

79720961 is a deficient number, since it is larger than the sum of its proper divisors (1306963).

79720961 is a wasteful number, since it uses less digits than its factorization.

79720961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306962.

The product of its (nonzero) digits is 47628, while the sum is 41.

The square root of 79720961 is about 8928.6595298511. The cubic root of 79720961 is about 430.3853783244.

The spelling of 79720961 in words is "seventy-nine million, seven hundred twenty thousand, nine hundred sixty-one".