90851391665 has 16 divisors (see below), whose sum is σ = 109526435712. Its totient is φ = 72344747904.

The previous prime is 90851391649. The next prime is 90851391713. The reversal of 90851391665 is 56619315809.

It is a cyclic number.

It is not a de Polignac number, because 90851391665 - 2⁴ = 90851391649 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9809717 + ... + 9818973.

It is an arithmetic number, because the mean of its divisors is an integer number (6845402232).

Almost surely, 2^90851391665 is an apocalyptic number.

It is an amenable number.

90851391665 is a deficient number, since it is larger than the sum of its proper divisors (18675044047).

90851391665 is a wasteful number, since it uses less digits than its factorization.

90851391665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18136.

The product of its (nonzero) digits is 1749600, while the sum is 53.

The spelling of 90851391665 in words is "ninety billion, eight hundred fifty-one million, three hundred ninety-one thousand, six hundred sixty-five".