21952393 has 4 divisors (see below), whose sum is σ = 21971988. Its totient is φ = 21932800.

The previous prime is 21952387. The next prime is 21952459. The reversal of 21952393 is 39325912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10582009 + 11370384 = 3253^2 + 3372^2 .

It is a cyclic number.

It is not a de Polignac number, because 21952393 - 2¹⁷ = 21821321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21952313) 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, 8008 + ... + 10393.

It is an arithmetic number, because the mean of its divisors is an integer number (5492997).

Almost surely, 2^21952393 is an apocalyptic number.

It is an amenable number.

21952393 is a deficient number, since it is larger than the sum of its proper divisors (19595).

21952393 is a wasteful number, since it uses less digits than its factorization.

21952393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19594.

The product of its digits is 14580, while the sum is 34.

The square root of 21952393 is about 4685.3380881213. The cubic root of 21952393 is about 280.0016709084.

The spelling of 21952393 in words is "twenty-one million, nine hundred fifty-two thousand, three hundred ninety-three".