21823425 has 60 divisors (see below), whose sum is σ = 43586620. Its totient is φ = 10730880.

The previous prime is 21823397. The next prime is 21823429. The reversal of 21823425 is 52432812.

21823425 = 636² + 637² + ... + 685².

21823425 is a `hidden beast` number, since 218 + 23 + 425 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 1896129 + 19927296 = 1377^2 + 4464^2 .

It is not a de Polignac number, because 21823425 - 2⁸ = 21823169 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21823429) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 25911 + ... + 26739.

Almost surely, 2^21823425 is an apocalyptic number.

21823425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21823425 is a deficient number, since it is larger than the sum of its proper divisors (21763195).

21823425 is a wasteful number, since it uses less digits than its factorization.

21823425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 864 (or 850 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21823425 is about 4671.5548803370. The cubic root of 21823425 is about 279.4522668135.

The spelling of 21823425 in words is "twenty-one million, eight hundred twenty-three thousand, four hundred twenty-five".