21188586969 has 45 divisors (see below), whose sum is σ = 33750266095. Its totient is φ = 12809544000.

The previous prime is 21188586967. The next prime is 21188587001. The reversal of 21188586969 is 96968588112.

The square root of 21188586969 is 145563.

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

It can be written as a sum of positive squares in only one way, i.e., 20977756569 + 210830400 = 144837^2 + 14520^2 .

It is not a de Polignac number, because 21188586969 - 2¹ = 21188586967 is a prime.

It is a super-2 number, since 2×21188586969² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21188586961) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 52839169 + ... + 52839569.

Almost surely, 2^21188586969 is an apocalyptic number.

21188586969 is the 145563-rd square number.

21188586969 is the 72782-nd centered octagonal number.

It is an amenable number.

21188586969 is a deficient number, since it is larger than the sum of its proper divisors (12561679126).

21188586969 is an frugal number, since it uses more digits than its factorization.

21188586969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 852 (or 415 counting only the distinct ones).

The product of its digits is 14929920, while the sum is 63.

The spelling of 21188586969 in words is "twenty-one billion, one hundred eighty-eight million, five hundred eighty-six thousand, nine hundred sixty-nine".