18539979 has 8 divisors (see below), whose sum is σ = 26174160. Its totient is φ = 11632896.

The previous prime is 18539977. The next prime is 18540007. The reversal of 18539979 is 97993581.

It is a happy number.

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

It is not a de Polignac number, because 18539979 - 2¹ = 18539977 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51), and also a Moran number because the ratio is a prime number: 363529 = 18539979 / (1 + 8 + 5 + 3 + 9 + 9 + 7 + 9).

It is not an unprimeable number, because it can be changed into a prime (18539971) 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, 181714 + ... + 181815.

It is an arithmetic number, because the mean of its divisors is an integer number (3271770).

Almost surely, 2^18539979 is an apocalyptic number.

18539979 is a deficient number, since it is larger than the sum of its proper divisors (7634181).

18539979 is a wasteful number, since it uses less digits than its factorization.

18539979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363549.

The product of its digits is 612360, while the sum is 51.

The square root of 18539979 is about 4305.8075897560. The cubic root of 18539979 is about 264.6690017144.

The spelling of 18539979 in words is "eighteen million, five hundred thirty-nine thousand, nine hundred seventy-nine".