20972911 has 2 divisors, whose sum is σ = 20972912. Its totient is φ = 20972910.

The previous prime is 20972909. The next prime is 20972921. The reversal of 20972911 is 11927902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20972911 - 2¹ = 20972909 is a prime.

Together with 20972909, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20972921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10486455 + 10486456.

It is an arithmetic number, because the mean of its divisors is an integer number (10486456).

Almost surely, 2^20972911 is an apocalyptic number.

20972911 is a deficient number, since it is larger than the sum of its proper divisors (1).

20972911 is an equidigital number, since it uses as much as digits as its factorization.

20972911 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 31.

The square root of 20972911 is about 4579.6190889636. The cubic root of 20972911 is about 275.7737372324.

The spelling of 20972911 in words is "twenty million, nine hundred seventy-two thousand, nine hundred eleven".