21283931 has 2 divisors, whose sum is σ = 21283932. Its totient is φ = 21283930.

The previous prime is 21283921. The next prime is 21283967. The reversal of 21283931 is 13938212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21283931 - 2²² = 17089627 is a prime.

It is a super-2 number, since 2×21283931² = 906011437625522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21283894 and 21283903.

It is not a weakly prime, because it can be changed into another prime (21283921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10641965 + 10641966.

It is an arithmetic number, because the mean of its divisors is an integer number (10641966).

Almost surely, 2^21283931 is an apocalyptic number.

21283931 is a deficient number, since it is larger than the sum of its proper divisors (1).

21283931 is an equidigital number, since it uses as much as digits as its factorization.

21283931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 29.

The square root of 21283931 is about 4613.4510943544. The cubic root of 21283931 is about 277.1302588674.

The spelling of 21283931 in words is "twenty-one million, two hundred eighty-three thousand, nine hundred thirty-one".