21233131 has 2 divisors, whose sum is σ = 21233132. Its totient is φ = 21233130.

The previous prime is 21233123. The next prime is 21233161. The reversal of 21233131 is 13133212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21233131 - 2³ = 21233123 is a prime.

It is a super-2 number, since 2×21233131² = 901691704126322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21233111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616565 + 10616566.

It is an arithmetic number, because the mean of its divisors is an integer number (10616566).

Almost surely, 2^21233131 is an apocalyptic number.

21233131 is a deficient number, since it is larger than the sum of its proper divisors (1).

21233131 is an equidigital number, since it uses as much as digits as its factorization.

21233131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108, while the sum is 16.

The square root of 21233131 is about 4607.9421654357. The cubic root of 21233131 is about 276.9096004976.

Adding to 21233131 its reverse (13133212), we get a palindrome (34366343).

The spelling of 21233131 in words is "twenty-one million, two hundred thirty-three thousand, one hundred thirty-one".