18979961 has 32 divisors (see below), whose sum is σ = 25955328. Its totient is φ = 13400640.

The previous prime is 18979957. The next prime is 18979999. The reversal of 18979961 is 16997981.

It is not a de Polignac number, because 18979961 - 2² = 18979957 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18979901) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66926 + ... + 67208.

It is an arithmetic number, because the mean of its divisors is an integer number (811104).

Almost surely, 2^18979961 is an apocalyptic number.

18979961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18979961 is a deficient number, since it is larger than the sum of its proper divisors (6975367).

18979961 is a wasteful number, since it uses less digits than its factorization.

18979961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381.

The product of its digits is 244944, while the sum is 50.

The square root of 18979961 is about 4356.5997061929. The cubic root of 18979961 is about 266.7463211698.

It can be divided in two parts, 18 and 979961, that added together give a palindrome (979979).

The spelling of 18979961 in words is "eighteen million, nine hundred seventy-nine thousand, nine hundred sixty-one".