21572125 has 32 divisors (see below), whose sum is σ = 29352960. Its totient is φ = 15768000.

The previous prime is 21572119. The next prime is 21572141. The reversal of 21572125 is 52127512.

It is a de Polignac number, because none of the positive numbers 2^k-21572125 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 21572125.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 73479 + ... + 73771.

It is an arithmetic number, because the mean of its divisors is an integer number (917280).

Almost surely, 2^21572125 is an apocalyptic number.

21572125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21572125 is a deficient number, since it is larger than the sum of its proper divisors (7780835).

21572125 is a wasteful number, since it uses less digits than its factorization.

21572125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358 (or 348 counting only the distinct ones).

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

The square root of 21572125 is about 4644.5801747844. The cubic root of 21572125 is about 278.3754781780.

Adding to 21572125 its reverse (52127512), we get a palindrome (73699637).

The spelling of 21572125 in words is "twenty-one million, five hundred seventy-two thousand, one hundred twenty-five".