215407864681 has 2 divisors, whose sum is σ = 215407864682. Its totient is φ = 215407864680.

The previous prime is 215407864631. The next prime is 215407864709. The reversal of 215407864681 is 186468704512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 211301105625 + 4106759056 = 459675^2 + 64084^2 .

It is a cyclic number.

It is not a de Polignac number, because 215407864681 - 2²¹ = 215405767529 is a prime.

It is a super-2 number, since 2×215407864681² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (215407864601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107703932340 + 107703932341.

It is an arithmetic number, because the mean of its divisors is an integer number (107703932341).

Almost surely, 2^215407864681 is an apocalyptic number.

It is an amenable number.

215407864681 is a deficient number, since it is larger than the sum of its proper divisors (1).

215407864681 is an equidigital number, since it uses as much as digits as its factorization.

215407864681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2580480, while the sum is 52.

The spelling of 215407864681 in words is "two hundred fifteen billion, four hundred seven million, eight hundred sixty-four thousand, six hundred eighty-one".