21323525 has 24 divisors (see below), whose sum is σ = 28283904. Its totient is φ = 15891200.

The previous prime is 21323521. The next prime is 21323527. The reversal of 21323525 is 52532312.

It is not a de Polignac number, because 21323525 - 2² = 21323521 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21323525.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 55484 + ... + 55866.

It is an arithmetic number, because the mean of its divisors is an integer number (1178496).

Almost surely, 2^21323525 is an apocalyptic number.

21323525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21323525 is a deficient number, since it is larger than the sum of its proper divisors (6960379).

21323525 is a wasteful number, since it uses less digits than its factorization.

21323525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 541 (or 536 counting only the distinct ones).

The product of its digits is 1800, while the sum is 23.

The square root of 21323525 is about 4617.7402482167. The cubic root of 21323525 is about 277.3019987339.

Adding to 21323525 its reverse (52532312), we get a palindrome (73855837).

The spelling of 21323525 in words is "twenty-one million, three hundred twenty-three thousand, five hundred twenty-five".