90911000021 has 2 divisors, whose sum is σ = 90911000022. Its totient is φ = 90911000020.

The previous prime is 90910999997. The next prime is 90911000039. The reversal of 90911000021 is 12000011909.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46438095025 + 44472904996 = 215495^2 + 210886^2 .

It is a cyclic number.

It is not a de Polignac number, because 90911000021 - 2⁶ = 90910999957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90911000041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45455500010 + 45455500011.

It is an arithmetic number, because the mean of its divisors is an integer number (45455500011).

Almost surely, 2^90911000021 is an apocalyptic number.

It is an amenable number.

90911000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

90911000021 is an equidigital number, since it uses as much as digits as its factorization.

90911000021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162, while the sum is 23.

The spelling of 90911000021 in words is "ninety billion, nine hundred eleven million, twenty-one", and thus it is an aban number.