215982967856881 has 27 divisors (see below), whose sum is σ = 224319124915041. Its totient is φ = 207948071589888.

The previous prime is 215982967856863. The next prime is 215982967856911. The reversal of 215982967856881 is 188658769289512.

The square root of 215982967856881 is 14696359.

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

It can be written as a sum of positive squares in 4 ways, for example, as 1566104576481 + 214416863280400 = 1251441^2 + 14642980^2 .

It is not a de Polignac number, because 215982967856881 - 2⁷ = 215982967856753 is a prime.

It is a super-2 number, since 2×215982967856881² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215982967856081) 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, 280862116465 + ... + 280862117233.

Almost surely, 2^{215982967856881} is an apocalyptic number.

215982967856881 is the 14696359-th square number.

215982967856881 is the 7348180-th centered octagonal number.

It is an amenable number.

215982967856881 is a deficient number, since it is larger than the sum of its proper divisors (8336157058160).

215982967856881 is an frugal number, since it uses more digits than its factorization.

215982967856881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2914 (or 1457 counting only the distinct ones).

The product of its digits is 8360755200, while the sum is 85.

The spelling of 215982967856881 in words is "two hundred fifteen trillion, nine hundred eighty-two billion, nine hundred sixty-seven million, eight hundred fifty-six thousand, eight hundred eighty-one".