21325520 has 40 divisors (see below), whose sum is σ = 51187200. Its totient is φ = 8254080.

The previous prime is 21325511. The next prime is 21325553. The reversal of 21325520 is 2552312.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21325492 and 21325501.

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 7 ways as a sum of consecutive naturals, for example, 1820 + ... + 6779.

It is an arithmetic number, because the mean of its divisors is an integer number (1279680).

Almost surely, 2^21325520 is an apocalyptic number.

21325520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21325520 is an abundant number, since it is smaller than the sum of its proper divisors (29861680).

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

21325520 is a wasteful number, since it uses less digits than its factorization.

21325520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8643 (or 8637 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 21325520 is about 4617.9562579132. The cubic root of 21325520 is about 277.3106464635.

Adding to 21325520 its reverse (2552312), we get a palindrome (23877832).

The spelling of 21325520 in words is "twenty-one million, three hundred twenty-five thousand, five hundred twenty".