21897125 has 16 divisors (see below), whose sum is σ = 27468480. Its totient is φ = 17427600.

The previous prime is 21897097. The next prime is 21897133. The reversal of 21897125 is 52179812.

It is not a de Polignac number, because 21897125 - 2¹⁸ = 21634981 is a prime.

It is a super-3 number, since 3×21897125³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35066 + ... + 35684.

It is an arithmetic number, because the mean of its divisors is an integer number (1716780).

Almost surely, 2^21897125 is an apocalyptic number.

21897125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21897125 is a deficient number, since it is larger than the sum of its proper divisors (5571355).

21897125 is an equidigital number, since it uses as much as digits as its factorization.

21897125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 917 (or 907 counting only the distinct ones).

The product of its digits is 10080, while the sum is 35.

The square root of 21897125 is about 4679.4363976872. The cubic root of 21897125 is about 279.7664932457.

It can be divided in two parts, 21897 and 125, that added together give a palindrome (22022).

The spelling of 21897125 in words is "twenty-one million, eight hundred ninety-seven thousand, one hundred twenty-five".