21271525 has 12 divisors (see below), whose sum is σ = 28774944. Its totient is φ = 15470000.

The previous prime is 21271519. The next prime is 21271553. The reversal of 21271525 is 52517212.

It is not a de Polignac number, because 21271525 - 2¹⁵ = 21238757 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a self number, because there is not a number n which added to its sum of digits gives 21271525.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38401 + ... + 38950.

It is an arithmetic number, because the mean of its divisors is an integer number (2397912).

Almost surely, 2^21271525 is an apocalyptic number.

21271525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21271525 is a deficient number, since it is larger than the sum of its proper divisors (7503419).

21271525 is a wasteful number, since it uses less digits than its factorization.

21271525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77372 (or 77367 counting only the distinct ones).

The product of its digits is 1400, while the sum is 25.

The square root of 21271525 is about 4612.1063517660. The cubic root of 21271525 is about 277.0764037438.

Adding to 21271525 its reverse (52517212), we get a palindrome (73788737).

The spelling of 21271525 in words is "twenty-one million, two hundred seventy-one thousand, five hundred twenty-five".