21303131 has 2 divisors, whose sum is σ = 21303132. Its totient is φ = 21303130.

The previous prime is 21303127. The next prime is 21303137. The reversal of 21303131 is 13130312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21303131 - 2² = 21303127 is a prime.

It is a super-2 number, since 2×21303131² = 907646780806322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21303137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10651565 + 10651566.

It is an arithmetic number, because the mean of its divisors is an integer number (10651566).

Almost surely, 2^21303131 is an apocalyptic number.

21303131 is a deficient number, since it is larger than the sum of its proper divisors (1).

21303131 is an equidigital number, since it uses as much as digits as its factorization.

21303131 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54, while the sum is 14.

The square root of 21303131 is about 4615.5314970218. The cubic root of 21303131 is about 277.2135658748.

Adding to 21303131 its reverse (13130312), we get a palindrome (34433443).

The spelling of 21303131 in words is "twenty-one million, three hundred three thousand, one hundred thirty-one".