91511218361 has 4 divisors (see below), whose sum is σ = 91512112500. Its totient is φ = 91510324224.

The previous prime is 91511218349. The next prime is 91511218369. The reversal of 91511218361 is 16381211519.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 65955998761 + 25555219600 = 256819^2 + 159860^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91511218361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91511218369) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 270236 + ... + 506013.

It is an arithmetic number, because the mean of its divisors is an integer number (22878028125).

Almost surely, 2^91511218361 is an apocalyptic number.

It is an amenable number.

91511218361 is a deficient number, since it is larger than the sum of its proper divisors (894139).

91511218361 is a wasteful number, since it uses less digits than its factorization.

91511218361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 894138.

The product of its digits is 12960, while the sum is 38.

The spelling of 91511218361 in words is "ninety-one billion, five hundred eleven million, two hundred eighteen thousand, three hundred sixty-one".