79523981 has 2 divisors, whose sum is σ = 79523982. Its totient is φ = 79523980.

The previous prime is 79523933. The next prime is 79523993. The reversal of 79523981 is 18932597.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75255625 + 4268356 = 8675^2 + 2066^2 .

It is an emirp because it is prime and its reverse (18932597) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-79523981 is a prime.

It is a super-2 number, since 2×79523981² = 12648127108176722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79523881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39761990 + 39761991.

It is an arithmetic number, because the mean of its divisors is an integer number (39761991).

Almost surely, 2^79523981 is an apocalyptic number.

It is an amenable number.

79523981 is a deficient number, since it is larger than the sum of its proper divisors (1).

79523981 is an equidigital number, since it uses as much as digits as its factorization.

79523981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 44.

The square root of 79523981 is about 8917.6219363685. The cubic root of 79523981 is about 430.0306107648.

The spelling of 79523981 in words is "seventy-nine million, five hundred twenty-three thousand, nine hundred eighty-one".