90390640969891 has 32 divisors (see below), whose sum is σ = 95041490890752. Its totient is φ = 85866489540480.

The previous prime is 90390640969793. The next prime is 90390640969913. The reversal of 90390640969891 is 19896904609309.

It is a cyclic number.

It is not a de Polignac number, because 90390640969891 - 2⁹ = 90390640969379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90390640963891) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 175341285 + ... + 175856041.

It is an arithmetic number, because the mean of its divisors is an integer number (2970046590336).

Almost surely, 2^{90390640969891} is an apocalyptic number.

90390640969891 is a deficient number, since it is larger than the sum of its proper divisors (4650849920861).

90390640969891 is a wasteful number, since it uses less digits than its factorization.

90390640969891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515379.

The product of its (nonzero) digits is 204073344, while the sum is 73.

The spelling of 90390640969891 in words is "ninety trillion, three hundred ninety billion, six hundred forty million, nine hundred sixty-nine thousand, eight hundred ninety-one".