20979477 has 24 divisors (see below), whose sum is σ = 32323200. Its totient is φ = 13074048.

The previous prime is 20979461. The next prime is 20979493. The reversal of 20979477 is 77497902.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20979461) and next prime (20979493).

It is not a de Polignac number, because 20979477 - 2⁴ = 20979461 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20979677) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12733 + ... + 14285.

It is an arithmetic number, because the mean of its divisors is an integer number (1346800).

Almost surely, 2^20979477 is an apocalyptic number.

It is an amenable number.

20979477 is a deficient number, since it is larger than the sum of its proper divisors (11343723).

20979477 is a wasteful number, since it uses less digits than its factorization.

20979477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1657 (or 1654 counting only the distinct ones).

The product of its (nonzero) digits is 222264, while the sum is 45.

The square root of 20979477 is about 4580.3359047127. The cubic root of 20979477 is about 275.8025131048.

The spelling of 20979477 in words is "twenty million, nine hundred seventy-nine thousand, four hundred seventy-seven".