979599991 has 4 divisors (see below), whose sum is σ = 1000442592. Its totient is φ = 958757392.

The previous prime is 979599983. The next prime is 979600021. The reversal of 979599991 is 199995979.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 979599991 - 2³ = 979599983 is a prime.

It is a super-2 number, since 2×979599991² = 1919232284734400162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (979599911) 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, 10421230 + ... + 10421323.

It is an arithmetic number, because the mean of its divisors is an integer number (250110648).

Almost surely, 2^979599991 is an apocalyptic number.

979599991 is a deficient number, since it is larger than the sum of its proper divisors (20842601).

979599991 is a wasteful number, since it uses less digits than its factorization.

979599991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20842600.

The product of its digits is 18600435, while the sum is 67.

The square root of 979599991 is about 31298.5621235225. The cubic root of 979599991 is about 993.1532256697.

The spelling of 979599991 in words is "nine hundred seventy-nine million, five hundred ninety-nine thousand, nine hundred ninety-one".