21897275 has 24 divisors (see below), whose sum is σ = 29216880. Its totient is φ = 16220160.

The previous prime is 21897247. The next prime is 21897283. The reversal of 21897275 is 57279812.

It is a de Polignac number, because none of the positive numbers 2^k-21897275 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28091 + ... + 28859.

It is an arithmetic number, because the mean of its divisors is an integer number (1217370).

Almost surely, 2^21897275 is an apocalyptic number.

21897275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21897275 is a deficient number, since it is larger than the sum of its proper divisors (7319605).

21897275 is a wasteful number, since it uses less digits than its factorization.

21897275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 863 (or 858 counting only the distinct ones).

The product of its digits is 70560, while the sum is 41.

The square root of 21897275 is about 4679.4524252310. The cubic root of 21897275 is about 279.7671320644.

The spelling of 21897275 in words is "twenty-one million, eight hundred ninety-seven thousand, two hundred seventy-five".