90091177921 has 2 divisors, whose sum is σ = 90091177922. Its totient is φ = 90091177920.

The previous prime is 90091177861. The next prime is 90091177973. The reversal of 90091177921 is 12977119009.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 86532458896 + 3558719025 = 294164^2 + 59655^2 .

It is an emirp because it is prime and its reverse (12977119009) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90091177921 - 2²⁵ = 90057623489 is a prime.

It is not a weakly prime, because it can be changed into another prime (90091171921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45045588960 + 45045588961.

It is an arithmetic number, because the mean of its divisors is an integer number (45045588961).

Almost surely, 2^90091177921 is an apocalyptic number.

It is an amenable number.

90091177921 is a deficient number, since it is larger than the sum of its proper divisors (1).

90091177921 is an equidigital number, since it uses as much as digits as its factorization.

90091177921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 71442, while the sum is 46.

The spelling of 90091177921 in words is "ninety billion, ninety-one million, one hundred seventy-seven thousand, nine hundred twenty-one".