21162931 has 2 divisors, whose sum is σ = 21162932. Its totient is φ = 21162930.

The previous prime is 21162907. The next prime is 21162937. The reversal of 21162931 is 13926112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21162931 is a prime.

It is a super-2 number, since 2×21162931² = 895739297021522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21162896 and 21162905.

It is not a weakly prime, because it can be changed into another prime (21162937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10581465 + 10581466.

It is an arithmetic number, because the mean of its divisors is an integer number (10581466).

Almost surely, 2^21162931 is an apocalyptic number.

21162931 is a deficient number, since it is larger than the sum of its proper divisors (1).

21162931 is an equidigital number, since it uses as much as digits as its factorization.

21162931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 25.

The square root of 21162931 is about 4600.3185759249. The cubic root of 21162931 is about 276.6040949770.

The spelling of 21162931 in words is "twenty-one million, one hundred sixty-two thousand, nine hundred thirty-one".