21753185168961 has 27 divisors (see below), whose sum is σ = 31507947034473. Its totient is φ = 14462227324800.

The previous prime is 21753185168903. The next prime is 21753185169017. The reversal of 21753185168961 is 16986158135712.

It is a happy number.

The square root of 21753185168961 is 4664031.

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

21753185168961 is a `hidden beast` number, since 2 + 1 + 7 + 5 + 31 + 8 + 516 + 89 + 6 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3757297640625 + 17995887528336 = 1938375^2 + 4242156^2 .

It is not a de Polignac number, because 21753185168961 - 2³¹ = 21751037685313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21753185168461) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 5610827355 + ... + 5610831231.

Almost surely, 2^{21753185168961} is an apocalyptic number.

21753185168961 is the 4664031-st square number.

21753185168961 is the 2332016-th centered octagonal number.

It is an amenable number.

21753185168961 is a deficient number, since it is larger than the sum of its proper divisors (9754761865512).

21753185168961 is an frugal number, since it uses more digits than its factorization.

21753185168961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8562 (or 4281 counting only the distinct ones).

The product of its digits is 21772800, while the sum is 63.

The spelling of 21753185168961 in words is "twenty-one trillion, seven hundred fifty-three billion, one hundred eighty-five million, one hundred sixty-eight thousand, nine hundred sixty-one".