215554989841 has 3 divisors (see below), whose sum is σ = 215555454121. Its totient is φ = 215554525562.

The previous prime is 215554989799. The next prime is 215554989851. The reversal of 215554989841 is 148989455512.

The square root of 215554989841 is 464279.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 215554989841 - 2¹⁵ = 215554957073 is a prime.

It is a super-2 number, since 2×215554989841² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 215554989841.

It is not an unprimeable number, because it can be changed into a prime (215554989851) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 232140 + ... + 696418.

Almost surely, 2^215554989841 is an apocalyptic number.

215554989841 is the 464279-th square number.

215554989841 is the 232140-th centered octagonal number.

It is an amenable number.

215554989841 is a deficient number, since it is larger than the sum of its proper divisors (464280).

215554989841 is an frugal number, since it uses more digits than its factorization.

215554989841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928558 (or 464279 counting only the distinct ones).

The product of its digits is 20736000, while the sum is 61.

The spelling of 215554989841 in words is "two hundred fifteen billion, five hundred fifty-four million, nine hundred eighty-nine thousand, eight hundred forty-one".