91298218873021 has 4 divisors (see below), whose sum is σ = 91298238470332. Its totient is φ = 91298199275712.

The previous prime is 91298218873009. The next prime is 91298218873027. The reversal of 91298218873021 is 12037881289219.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 80434530360900 + 10863688512121 = 8968530^2 + 3296011^2 .

It is a cyclic number.

It is not a de Polignac number, because 91298218873021 - 2⁷ = 91298218872893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91298218873027) 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, 1642075 + ... + 13612231.

It is an arithmetic number, because the mean of its divisors is an integer number (22824559617583).

Almost surely, 2^{91298218873021} is an apocalyptic number.

It is an amenable number.

91298218873021 is a deficient number, since it is larger than the sum of its proper divisors (19597311).

91298218873021 is a wasteful number, since it uses less digits than its factorization.

91298218873021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19597310.

The product of its (nonzero) digits is 6967296, while the sum is 61.

The spelling of 91298218873021 in words is "ninety-one trillion, two hundred ninety-eight billion, two hundred eighteen million, eight hundred seventy-three thousand, twenty-one".