91993878401 has 2 divisors, whose sum is σ = 91993878402. Its totient is φ = 91993878400.

The previous prime is 91993878359. The next prime is 91993878407. The reversal of 91993878401 is 10487839919.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71580327025 + 20413551376 = 267545^2 + 142876^2 .

It is an emirp because it is prime and its reverse (10487839919) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91993878401 - 2¹⁸ = 91993616257 is a prime.

It is not a weakly prime, because it can be changed into another prime (91993878407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45996939200 + 45996939201.

It is an arithmetic number, because the mean of its divisors is an integer number (45996939201).

Almost surely, 2^91993878401 is an apocalyptic number.

It is an amenable number.

91993878401 is a deficient number, since it is larger than the sum of its proper divisors (1).

91993878401 is an equidigital number, since it uses as much as digits as its factorization.

91993878401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3919104, while the sum is 59.

The spelling of 91993878401 in words is "ninety-one billion, nine hundred ninety-three million, eight hundred seventy-eight thousand, four hundred one".