21235775625 has 135 divisors (see below), whose sum is σ = 40298749491. Its totient is φ = 10771992000.

The previous prime is 21235775599. The next prime is 21235775647. The reversal of 21235775625 is 52657753212.

The square root of 21235775625 is 145725.

It is a perfect power (a square), and thus also a powerful number.

21235775625 is a `hidden beast` number, since 2 + 1 + 2 + 3 + 577 + 56 + 25 = 666.

It can be written as a sum of positive squares in 7 ways, for example, as 15882804729 + 5352970896 = 126027^2 + 73164^2 .

It is not a de Polignac number, because 21235775625 - 2²⁹ = 20698904713 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 316951842 + ... + 316951908.

Almost surely, 2^21235775625 is an apocalyptic number.

21235775625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21235775625 is the 145725-th square number.

21235775625 is the 72863-rd centered octagonal number.

It is an amenable number.

21235775625 is a deficient number, since it is larger than the sum of its proper divisors (19062973866).

21235775625 is an frugal number, since it uses more digits than its factorization.

21235775625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218 (or 104 counting only the distinct ones).

The product of its digits is 882000, while the sum is 45.

The spelling of 21235775625 in words is "twenty-one billion, two hundred thirty-five million, seven hundred seventy-five thousand, six hundred twenty-five".