79128661 has 2 divisors, whose sum is σ = 79128662. Its totient is φ = 79128660.

The previous prime is 79128653. The next prime is 79128677. The reversal of 79128661 is 16682197.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50836900 + 28291761 = 7130^2 + 5319^2 .

It is a cyclic number.

It is not a de Polignac number, because 79128661 - 2³ = 79128653 is a prime.

It is a super-2 number, since 2×79128661² = 12522689983305842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79128641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39564330 + 39564331.

It is an arithmetic number, because the mean of its divisors is an integer number (39564331).

Almost surely, 2^79128661 is an apocalyptic number.

It is an amenable number.

79128661 is a deficient number, since it is larger than the sum of its proper divisors (1).

79128661 is an equidigital number, since it uses as much as digits as its factorization.

79128661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 40.

The square root of 79128661 is about 8895.4292195487. The cubic root of 79128661 is about 429.3168546816.

The spelling of 79128661 in words is "seventy-nine million, one hundred twenty-eight thousand, six hundred sixty-one".