91180001021 has 2 divisors, whose sum is σ = 91180001022. Its totient is φ = 91180001020.

The previous prime is 91180000993. The next prime is 91180001027. The reversal of 91180001021 is 12010008119.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75905760100 + 15274240921 = 275510^2 + 123589^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91180001021 is a prime.

It is a super-2 number, since 2×91180001021² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91180001027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45590000510 + 45590000511.

It is an arithmetic number, because the mean of its divisors is an integer number (45590000511).

Almost surely, 2^91180001021 is an apocalyptic number.

It is an amenable number.

91180001021 is a deficient number, since it is larger than the sum of its proper divisors (1).

91180001021 is an equidigital number, since it uses as much as digits as its factorization.

91180001021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 23.

The spelling of 91180001021 in words is "ninety-one billion, one hundred eighty million, one thousand, twenty-one".