20979578 has 16 divisors (see below), whose sum is σ = 32538240. Its totient is φ = 10139136.

The previous prime is 20979559. The next prime is 20979583. The reversal of 20979578 is 87597902.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6458 + ... + 9146.

It is an arithmetic number, because the mean of its divisors is an integer number (2033640).

Almost surely, 2^20979578 is an apocalyptic number.

20979578 is a deficient number, since it is larger than the sum of its proper divisors (11558662).

20979578 is a wasteful number, since it uses less digits than its factorization.

20979578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2821.

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

The square root of 20979578 is about 4580.3469300916. The cubic root of 20979578 is about 275.8029556962.

The spelling of 20979578 in words is "twenty million, nine hundred seventy-nine thousand, five hundred seventy-eight".