215800198849 has 9 divisors (see below), whose sum is σ = 217779810339. Its totient is φ = 213838433760.

The previous prime is 215800198841. The next prime is 215800198903. The reversal of 215800198849 is 948891008512.

The square root of 215800198849 is 464543.

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., 3802572225 + 211997626624 = 61665^2 + 460432^2 .

It is not a de Polignac number, because 215800198849 - 2³ = 215800198841 is a prime.

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 215800198849.

It is not an unprimeable number, because it can be changed into a prime (215800198841) 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, 52491304 + ... + 52495414.

Almost surely, 2^215800198849 is an apocalyptic number.

215800198849 is the 464543-rd square number.

215800198849 is the 232272-nd centered octagonal number.

It is an amenable number.

215800198849 is a deficient number, since it is larger than the sum of its proper divisors (1979611490).

215800198849 is an frugal number, since it uses more digits than its factorization.

215800198849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8448 (or 4224 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 55.

The spelling of 215800198849 in words is "two hundred fifteen billion, eight hundred million, one hundred ninety-eight thousand, eight hundred forty-nine".