20972015 has 4 divisors (see below), whose sum is σ = 25166424. Its totient is φ = 16777608.

The previous prime is 20971997. The next prime is 20972023. The reversal of 20972015 is 51027902.

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 20972015 - 2²² = 16777711 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2097197 + ... + 2097206.

It is an arithmetic number, because the mean of its divisors is an integer number (6291606).

Almost surely, 2^20972015 is an apocalyptic number.

20972015 is a deficient number, since it is larger than the sum of its proper divisors (4194409).

20972015 is an equidigital number, since it uses as much as digits as its factorization.

20972015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4194408.

The product of its (nonzero) digits is 1260, while the sum is 26.

The square root of 20972015 is about 4579.5212631890. The cubic root of 20972015 is about 275.7698099953.

Adding to 20972015 its reverse (51027902), we get a palindrome (71999917).

The spelling of 20972015 in words is "twenty million, nine hundred seventy-two thousand, fifteen".