21432813 has 8 divisors (see below), whose sum is σ = 28606176. Its totient is φ = 14274000.

The previous prime is 21432809. The next prime is 21432821. The reversal of 21432813 is 31823412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21432813 - 2² = 21432809 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21432833) 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 in 7 ways as a sum of consecutive naturals, for example, 463 + ... + 6563.

It is an arithmetic number, because the mean of its divisors is an integer number (3575772).

Almost surely, 2^21432813 is an apocalyptic number.

It is an amenable number.

21432813 is a deficient number, since it is larger than the sum of its proper divisors (7173363).

21432813 is a wasteful number, since it uses less digits than its factorization.

21432813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7275.

The product of its digits is 1152, while the sum is 24.

The square root of 21432813 is about 4629.5586182702. The cubic root of 21432813 is about 277.7749373161.

The spelling of 21432813 in words is "twenty-one million, four hundred thirty-two thousand, eight hundred thirteen".