20881117009 has 9 divisors (see below), whose sum is σ = 21147874779. Its totient is φ = 20617688040.

The previous prime is 20881116979. The next prime is 20881117057. The reversal of 20881117009 is 90071118802.

The square root of 20881117009 is 144503.

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., 23980609 + 20857136400 = 4897^2 + 144420^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20881117009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20881127009) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 11992879 + ... + 11994619.

Almost surely, 2^20881117009 is an apocalyptic number.

20881117009 is the 144503-rd square number.

20881117009 is the 72252-nd centered octagonal number.

It is an amenable number.

20881117009 is a deficient number, since it is larger than the sum of its proper divisors (266757770).

20881117009 is an frugal number, since it uses more digits than its factorization.

20881117009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3648 (or 1824 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 37.

The spelling of 20881117009 in words is "twenty billion, eight hundred eighty-one million, one hundred seventeen thousand, nine".