79721947 has 2 divisors, whose sum is σ = 79721948. Its totient is φ = 79721946.

The previous prime is 79721927. The next prime is 79721951. The reversal of 79721947 is 74912797.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 79721947 - 2⁷ = 79721819 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 79721897 and 79721906.

It is not a weakly prime, because it can be changed into another prime (79721927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39860973 + 39860974.

It is an arithmetic number, because the mean of its divisors is an integer number (39860974).

Almost surely, 2^79721947 is an apocalyptic number.

79721947 is a deficient number, since it is larger than the sum of its proper divisors (1).

79721947 is an equidigital number, since it uses as much as digits as its factorization.

79721947 is an evil number, because the sum of its binary digits is even.

The product of its digits is 222264, while the sum is 46.

The square root of 79721947 is about 8928.7147451355. The cubic root of 79721947 is about 430.3871526726.

The spelling of 79721947 in words is "seventy-nine million, seven hundred twenty-one thousand, nine hundred forty-seven".