79978661 has 8 divisors (see below), whose sum is σ = 91587840. Its totient is φ = 68415408.

The previous prime is 79978649. The next prime is 79978663. The reversal of 79978661 is 16687997.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 79978661 - 2⁶ = 79978597 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79978663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7661 + ... + 14786.

It is an arithmetic number, because the mean of its divisors is an integer number (11448480).

Almost surely, 2^79978661 is an apocalyptic number.

It is an amenable number.

79978661 is a deficient number, since it is larger than the sum of its proper divisors (11609179).

79978661 is a wasteful number, since it uses less digits than its factorization.

79978661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22963.

The product of its digits is 1143072, while the sum is 53.

The square root of 79978661 is about 8943.0789440774. The cubic root of 79978661 is about 430.8486233646.

The spelling of 79978661 in words is "seventy-nine million, nine hundred seventy-eight thousand, six hundred sixty-one".