215555161 has 2 divisors, whose sum is σ = 215555162. Its totient is φ = 215555160.

The previous prime is 215555141. The next prime is 215555177. The reversal of 215555161 is 161555512.

215555161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 208975936 + 6579225 = 14456^2 + 2565^2 .

It is a cyclic number.

It is not a de Polignac number, because 215555161 - 2¹⁵ = 215522393 is a prime.

It is not a weakly prime, because it can be changed into another prime (215555111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107777580 + 107777581.

It is an arithmetic number, because the mean of its divisors is an integer number (107777581).

Almost surely, 2^215555161 is an apocalyptic number.

It is an amenable number.

215555161 is a deficient number, since it is larger than the sum of its proper divisors (1).

215555161 is an equidigital number, since it uses as much as digits as its factorization.

215555161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7500, while the sum is 31.

The square root of 215555161 is about 14681.7969268070. The cubic root of 215555161 is about 599.5878289603.

The spelling of 215555161 in words is "two hundred fifteen million, five hundred fifty-five thousand, one hundred sixty-one".