21455525 has 24 divisors (see below), whose sum is σ = 32747904. Its totient is φ = 13579200.

The previous prime is 21455521. The next prime is 21455537. The reversal of 21455525 is 52555412.

It is not a de Polignac number, because 21455525 - 2² = 21455521 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21455521) 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, 2441 + ... + 6990.

It is an arithmetic number, because the mean of its divisors is an integer number (1364496).

Almost surely, 2^21455525 is an apocalyptic number.

21455525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21455525 is a deficient number, since it is larger than the sum of its proper divisors (11292379).

21455525 is a wasteful number, since it uses less digits than its factorization.

21455525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9461 (or 9456 counting only the distinct ones).

The product of its digits is 10000, while the sum is 29.

The square root of 21455525 is about 4632.0109024051. The cubic root of 21455525 is about 277.8730205252.

The spelling of 21455525 in words is "twenty-one million, four hundred fifty-five thousand, five hundred twenty-five".