79775921 has 4 divisors (see below), whose sum is σ = 79826292. Its totient is φ = 79725552.

The previous prime is 79775909. The next prime is 79775923. The reversal of 79775921 is 12957797.

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 25959025 + 53816896 = 5095^2 + 7336^2 .

It is a cyclic number.

It is not a de Polignac number, because 79775921 - 2²² = 75581617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79775923) 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, 22730 + ... + 26003.

It is an arithmetic number, because the mean of its divisors is an integer number (19956573).

Almost surely, 2^79775921 is an apocalyptic number.

It is an amenable number.

79775921 is a deficient number, since it is larger than the sum of its proper divisors (50371).

79775921 is a wasteful number, since it uses less digits than its factorization.

79775921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50370.

The product of its digits is 277830, while the sum is 47.

The square root of 79775921 is about 8931.7367292145. The cubic root of 79775921 is about 430.4842588298.

The spelling of 79775921 in words is "seventy-nine million, seven hundred seventy-five thousand, nine hundred twenty-one".