20654979 has 4 divisors (see below), whose sum is σ = 27539976. Its totient is φ = 13769984.

The previous prime is 20654951. The next prime is 20654993. The reversal of 20654979 is 97945602.

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 20654979 - 2²⁰ = 19606403 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20654979.

It is not an unprimeable number, because it can be changed into a prime (20654999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3442494 + ... + 3442499.

It is an arithmetic number, because the mean of its divisors is an integer number (6884994).

Almost surely, 2^20654979 is an apocalyptic number.

20654979 is a deficient number, since it is larger than the sum of its proper divisors (6884997).

20654979 is an equidigital number, since it uses as much as digits as its factorization.

20654979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6884996.

The product of its (nonzero) digits is 136080, while the sum is 42.

The square root of 20654979 is about 4544.7749119181. The cubic root of 20654979 is about 274.3731352277.

The spelling of 20654979 in words is "twenty million, six hundred fifty-four thousand, nine hundred seventy-nine".