21803925 has 96 divisors (see below), whose sum is σ = 44997120. Its totient is φ = 9158400.

The previous prime is 21803897. The next prime is 21803933. The reversal of 21803925 is 52930812.

It is a happy number.

It is not a de Polignac number, because 21803925 - 2⁶ = 21803861 is a prime.

It is a super-2 number, since 2×21803925² = 950822290811250, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21803892 and 21803901.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 203722 + ... + 203828.

It is an arithmetic number, because the mean of its divisors is an integer number (468720).

Almost surely, 2^21803925 is an apocalyptic number.

21803925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21803925 is an abundant number, since it is smaller than the sum of its proper divisors (23193195).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21803925 is a wasteful number, since it uses less digits than its factorization.

21803925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 21803925 is about 4669.4673143732. The cubic root of 21803925 is about 279.3690085248.

It can be divided in two parts, 2180 and 3925, that added together give a triangular number (6105 = T₁₁₀).

The spelling of 21803925 in words is "twenty-one million, eight hundred three thousand, nine hundred twenty-five".