21130331 has 2 divisors, whose sum is σ = 21130332. Its totient is φ = 21130330.

The previous prime is 21130321. The next prime is 21130397. The reversal of 21130331 is 13303112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21130331 - 2⁶ = 21130267 is a prime.

It is a super-2 number, since 2×21130331² = 892981776339122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21130301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565165 + 10565166.

It is an arithmetic number, because the mean of its divisors is an integer number (10565166).

Almost surely, 2^21130331 is an apocalyptic number.

21130331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21130331 is an equidigital number, since it uses as much as digits as its factorization.

21130331 is an evil number, because the sum of its binary digits is even.

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

The square root of 21130331 is about 4596.7739774759. The cubic root of 21130331 is about 276.4619922970.

Adding to 21130331 its reverse (13303112), we get a palindrome (34433443).

The spelling of 21130331 in words is "twenty-one million, one hundred thirty thousand, three hundred thirty-one".