21897135 has 40 divisors (see below), whose sum is σ = 42282240. Its totient is φ = 10777536.

The previous prime is 21897133. The next prime is 21897149. The reversal of 21897135 is 53179812.

It is not a de Polignac number, because 21897135 - 2¹ = 21897133 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21897135.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21897133) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3186 + ... + 7344.

It is an arithmetic number, because the mean of its divisors is an integer number (1057056).

Almost surely, 2^21897135 is an apocalyptic number.

21897135 is a deficient number, since it is larger than the sum of its proper divisors (20385105).

21897135 is a wasteful number, since it uses less digits than its factorization.

21897135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4189 (or 4180 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 21897135 is about 4679.4374661918. The cubic root of 21897135 is about 279.7665358337.

The spelling of 21897135 in words is "twenty-one million, eight hundred ninety-seven thousand, one hundred thirty-five".