215538276121 has 27 divisors (see below), whose sum is σ = 259785722079. Its totient is φ = 178298508528.

The previous prime is 215538276113. The next prime is 215538276197. The reversal of 215538276121 is 121672835512.

The square root of 215538276121 is 464261.

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., 113023043721 + 102515232400 = 336189^2 + 320180^2 .

It is not a de Polignac number, because 215538276121 - 2³ = 215538276113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215538276101) 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, 94243840 + ... + 94246126.

Almost surely, 2^215538276121 is an apocalyptic number.

215538276121 is the 464261-st square number.

215538276121 is the 232131-st centered octagonal number.

It is an amenable number.

215538276121 is a deficient number, since it is larger than the sum of its proper divisors (44247445958).

215538276121 is an frugal number, since it uses more digits than its factorization.

215538276121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4646 (or 2323 counting only the distinct ones).

The product of its digits is 201600, while the sum is 43.

The spelling of 215538276121 in words is "two hundred fifteen billion, five hundred thirty-eight million, two hundred seventy-six thousand, one hundred twenty-one".