21432313 has 4 divisors (see below), whose sum is σ = 24494080. Its totient is φ = 18370548.

The previous prime is 21432311. The next prime is 21432317. The reversal of 21432313 is 31323412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21432313 - 2¹ = 21432311 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21432311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1530873 + ... + 1530886.

It is an arithmetic number, because the mean of its divisors is an integer number (6123520).

Almost surely, 2^21432313 is an apocalyptic number.

It is an amenable number.

21432313 is a deficient number, since it is larger than the sum of its proper divisors (3061767).

21432313 is an equidigital number, since it uses as much as digits as its factorization.

21432313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3061766.

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

The square root of 21432313 is about 4629.5046171270. The cubic root of 21432313 is about 277.7727772552.

Adding to 21432313 its reverse (31323412), we get a palindrome (52755725).

The spelling of 21432313 in words is "twenty-one million, four hundred thirty-two thousand, three hundred thirteen".