20578979 has 4 divisors (see below), whose sum is σ = 20619000. Its totient is φ = 20538960.

The previous prime is 20578963. The next prime is 20578981. The reversal of 20578979 is 97987502.

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 20578979 - 2⁴ = 20578963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20578939) 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, 19229 + ... + 20270.

It is an arithmetic number, because the mean of its divisors is an integer number (5154750).

Almost surely, 2^20578979 is an apocalyptic number.

20578979 is a deficient number, since it is larger than the sum of its proper divisors (40021).

20578979 is an equidigital number, since it uses as much as digits as its factorization.

20578979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40020.

The product of its (nonzero) digits is 317520, while the sum is 47.

The square root of 20578979 is about 4536.4059562610. The cubic root of 20578979 is about 274.0362029703.

The spelling of 20578979 in words is "twenty million, five hundred seventy-eight thousand, nine hundred seventy-nine".