21956525 has 24 divisors (see below), whose sum is σ = 28831488. Its totient is φ = 16560000.

The previous prime is 21956479. The next prime is 21956527. The reversal of 21956525 is 52565912.

It is not a de Polignac number, because 21956525 - 2⁶ = 21956461 is a prime.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21956527) 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, 31430 + ... + 32120.

It is an arithmetic number, because the mean of its divisors is an integer number (1201312).

Almost surely, 2^21956525 is an apocalyptic number.

21956525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21956525 is a deficient number, since it is larger than the sum of its proper divisors (6874963).

21956525 is a wasteful number, since it uses less digits than its factorization.

21956525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 773 (or 768 counting only the distinct ones).

The product of its digits is 27000, while the sum is 35.

The square root of 21956525 is about 4685.7790174100. The cubic root of 21956525 is about 280.0192376238.

The spelling of 21956525 in words is "twenty-one million, nine hundred fifty-six thousand, five hundred twenty-five".