21571561125 has 48 divisors (see below), whose sum is σ = 39249976896. Its totient is φ = 11397247200.

The previous prime is 21571561087. The next prime is 21571561129. The reversal of 21571561125 is 52116517512.

21571561125 is a `hidden beast` number, since 2 + 1 + 5 + 7 + 15 + 611 + 25 = 666.

It is not a de Polignac number, because 21571561125 - 2¹⁷ = 21571430053 is a prime.

It is a super-2 number, since 2×21571561125² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21571561125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21571561129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 30774 + ... + 209976.

It is an arithmetic number, because the mean of its divisors is an integer number (817707852).

Almost surely, 2^21571561125 is an apocalyptic number.

21571561125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21571561125 is a deficient number, since it is larger than the sum of its proper divisors (17678415771).

21571561125 is a wasteful number, since it uses less digits than its factorization.

21571561125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179331 (or 179318 counting only the distinct ones).

The product of its digits is 21000, while the sum is 36.

The spelling of 21571561125 in words is "twenty-one billion, five hundred seventy-one million, five hundred sixty-one thousand, one hundred twenty-five".