21525272 has 8 divisors (see below), whose sum is σ = 40359900. Its totient is φ = 10762632.

The previous prime is 21525227. The next prime is 21525277. The reversal of 21525272 is 27252512.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1345322 + ... + 1345337.

Almost surely, 2^21525272 is an apocalyptic number.

It is an amenable number.

21525272 is a deficient number, since it is larger than the sum of its proper divisors (18834628).

21525272 is a wasteful number, since it uses less digits than its factorization.

21525272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2690665 (or 2690661 counting only the distinct ones).

The product of its digits is 2800, while the sum is 26.

The square root of 21525272 is about 4639.5335972488. The cubic root of 21525272 is about 278.1737953691.

Adding to 21525272 its reverse (27252512), we get a palindrome (48777784).

The spelling of 21525272 in words is "twenty-one million, five hundred twenty-five thousand, two hundred seventy-two".