21732393 has 4 divisors (see below), whose sum is σ = 28976528. Its totient is φ = 14488260.

The previous prime is 21732383. The next prime is 21732413. The reversal of 21732393 is 39323712.

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 21732393 - 2¹² = 21728297 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21732393.

It is not an unprimeable number, because it can be changed into a prime (21732323) 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, 3622063 + ... + 3622068.

It is an arithmetic number, because the mean of its divisors is an integer number (7244132).

Almost surely, 2^21732393 is an apocalyptic number.

It is an amenable number.

21732393 is a deficient number, since it is larger than the sum of its proper divisors (7244135).

21732393 is an equidigital number, since it uses as much as digits as its factorization.

21732393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7244134.

The product of its digits is 6804, while the sum is 30.

The square root of 21732393 is about 4661.8014758246. The cubic root of 21732393 is about 279.0631657704.

The spelling of 21732393 in words is "twenty-one million, seven hundred thirty-two thousand, three hundred ninety-three".