21873825 has 36 divisors (see below), whose sum is σ = 39790608. Its totient is φ = 11484000.

The previous prime is 21873823. The next prime is 21873829. The reversal of 21873825 is 52837812.

It is not a de Polignac number, because 21873825 - 2¹ = 21873823 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21873825.

It is not an unprimeable number, because it can be changed into a prime (21873821) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 14350 + ... + 15800.

Almost surely, 2^21873825 is an apocalyptic number.

21873825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21873825 is a deficient number, since it is larger than the sum of its proper divisors (17916783).

21873825 is a wasteful number, since it uses less digits than its factorization.

21873825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1534 (or 1526 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 21873825 is about 4676.9461189969. The cubic root of 21873825 is about 279.6672279659.

The spelling of 21873825 in words is "twenty-one million, eight hundred seventy-three thousand, eight hundred twenty-five".