21432331 has 2 divisors, whose sum is σ = 21432332. Its totient is φ = 21432330.

The previous prime is 21432317. The next prime is 21432347. The reversal of 21432331 is 13323412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21432331 - 2¹⁵ = 21399563 is a prime.

It is a super-2 number, since 2×21432331² = 918689624187122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21432299 and 21432308.

It is not a weakly prime, because it can be changed into another prime (21432311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10716165 + 10716166.

It is an arithmetic number, because the mean of its divisors is an integer number (10716166).

Almost surely, 2^21432331 is an apocalyptic number.

21432331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21432331 is an equidigital number, since it uses as much as digits as its factorization.

21432331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 19.

The square root of 21432331 is about 4629.5065611791. The cubic root of 21432331 is about 277.7728550179.

Adding to 21432331 its reverse (13323412), we get a palindrome (34755743).

The spelling of 21432331 in words is "twenty-one million, four hundred thirty-two thousand, three hundred thirty-one".