21231925 has 24 divisors (see below), whose sum is σ = 30935520. Its totient is φ = 14251200.

The previous prime is 21231923. The next prime is 21231937. The reversal of 21231925 is 52913212.

It is a happy number.

It is not a de Polignac number, because 21231925 - 2¹ = 21231923 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a self number, because there is not a number n which added to its sum of digits gives 21231925.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231923) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 606 + ... + 6544.

It is an arithmetic number, because the mean of its divisors is an integer number (1288980).

Almost surely, 2^21231925 is an apocalyptic number.

21231925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21231925 is a deficient number, since it is larger than the sum of its proper divisors (9703595).

21231925 is a wasteful number, since it uses less digits than its factorization.

21231925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5973 (or 5968 counting only the distinct ones).

The product of its digits is 1080, while the sum is 25.

The square root of 21231925 is about 4607.8113025600. The cubic root of 21231925 is about 276.9043577585.

The spelling of 21231925 in words is "twenty-one million, two hundred thirty-one thousand, nine hundred twenty-five".