21897353 has 4 divisors (see below), whose sum is σ = 22256388. Its totient is φ = 21538320.

The previous prime is 21897313. The next prime is 21897371. The reversal of 21897353 is 35379812.

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 11580409 + 10316944 = 3403^2 + 3212^2 .

It is a cyclic number.

It is not a de Polignac number, because 21897353 - 2⁶ = 21897289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21897313) 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, 179426 + ... + 179547.

It is an arithmetic number, because the mean of its divisors is an integer number (5564097).

Almost surely, 2^21897353 is an apocalyptic number.

It is an amenable number.

21897353 is a deficient number, since it is larger than the sum of its proper divisors (359035).

21897353 is an equidigital number, since it uses as much as digits as its factorization.

21897353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359034.

The product of its digits is 45360, while the sum is 38.

The square root of 21897353 is about 4679.4607595320. The cubic root of 21897353 is about 279.7674642490.

The spelling of 21897353 in words is "twenty-one million, eight hundred ninety-seven thousand, three hundred fifty-three".