21800925 has 18 divisors (see below), whose sum is σ = 39048282. Its totient is φ = 11627040.

The previous prime is 21800921. The next prime is 21800963. The reversal of 21800925 is 52900812.

It can be written as a sum of positive squares in 3 ways, for example, as 622521 + 21178404 = 789^2 + 4602^2 .

It is not a de Polignac number, because 21800925 - 2² = 21800921 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21800921) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 48222 + ... + 48671.

It is an arithmetic number, because the mean of its divisors is an integer number (2169349).

Almost surely, 2^21800925 is an apocalyptic number.

21800925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21800925 is a deficient number, since it is larger than the sum of its proper divisors (17247357).

21800925 is a wasteful number, since it uses less digits than its factorization.

21800925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96909 (or 96901 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 21800925 is about 4669.1460675374. The cubic root of 21800925 is about 279.3561951518.

The spelling of 21800925 in words is "twenty-one million, eight hundred thousand, nine hundred twenty-five".