21201931 has 2 divisors, whose sum is σ = 21201932. Its totient is φ = 21201930.

The previous prime is 21201919. The next prime is 21201937. The reversal of 21201931 is 13910212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21201931 - 2⁹ = 21201419 is a prime.

It is a super-2 number, since 2×21201931² = 899043756257522, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201899 and 21201908.

It is not a weakly prime, because it can be changed into another prime (21201937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600965 + 10600966.

It is an arithmetic number, because the mean of its divisors is an integer number (10600966).

Almost surely, 2^21201931 is an apocalyptic number.

21201931 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201931 is an equidigital number, since it uses as much as digits as its factorization.

21201931 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 21201931 is about 4604.5554617140. Note that the first 3 decimals coincide. The cubic root of 21201931 is about 276.7739035269.

The spelling of 21201931 in words is "twenty-one million, two hundred one thousand, nine hundred thirty-one".