21840325 has 48 divisors (see below), whose sum is σ = 31872960. Its totient is φ = 14699520.

The previous prime is 21840319. The next prime is 21840361. The reversal of 21840325 is 52304812.

It is not a de Polignac number, because 21840325 - 2⁷ = 21840197 is a prime.

It is a super-2 number, since 2×21840325² = 953999592211250, which contains 22 as substring.

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 21840325.

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 325942 + ... + 326008.

It is an arithmetic number, because the mean of its divisors is an integer number (664020).

Almost surely, 2^21840325 is an apocalyptic number.

21840325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21840325 is a deficient number, since it is larger than the sum of its proper divisors (10032635).

21840325 is a wasteful number, since it uses less digits than its factorization.

21840325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 21840325 is about 4673.3633498798. The cubic root of 21840325 is about 279.5243838887.

The spelling of 21840325 in words is "twenty-one million, eight hundred forty thousand, three hundred twenty-five".