215908173281 has 2 divisors, whose sum is σ = 215908173282. Its totient is φ = 215908173280.

The previous prime is 215908173251. The next prime is 215908173301. The reversal of 215908173281 is 182371809512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 204108782656 + 11799390625 = 451784^2 + 108625^2 .

It is a cyclic number.

It is not a de Polignac number, because 215908173281 - 2²² = 215903978977 is a prime.

It is a super-2 number, since 2×215908173281² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (215908173251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107954086640 + 107954086641.

It is an arithmetic number, because the mean of its divisors is an integer number (107954086641).

Almost surely, 2^215908173281 is an apocalyptic number.

It is an amenable number.

215908173281 is a deficient number, since it is larger than the sum of its proper divisors (1).

215908173281 is an equidigital number, since it uses as much as digits as its factorization.

215908173281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 47.

The spelling of 215908173281 in words is "two hundred fifteen billion, nine hundred eight million, one hundred seventy-three thousand, two hundred eighty-one".