21238525 has 72 divisors (see below), whose sum is σ = 35622720. Its totient is φ = 12249600.

The previous prime is 21238519. The next prime is 21238543. The reversal of 21238525 is 52583212.

It is not a de Polignac number, because 21238525 - 2¹¹ = 21236477 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21238493 and 21238502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 359946 + ... + 360004.

It is an arithmetic number, because the mean of its divisors is an integer number (494760).

Almost surely, 2^21238525 is an apocalyptic number.

21238525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21238525 is a deficient number, since it is larger than the sum of its proper divisors (14384195).

21238525 is a wasteful number, since it uses less digits than its factorization.

21238525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115 (or 99 counting only the distinct ones).

The product of its digits is 4800, while the sum is 28.

The square root of 21238525 is about 4608.5274220731. The cubic root of 21238525 is about 276.9330469365.

It can be divided in two parts, 2123 and 8525, that added together give a cube (10648 = 22³).

The spelling of 21238525 in words is "twenty-one million, two hundred thirty-eight thousand, five hundred twenty-five".