91777425881 has 2 divisors, whose sum is σ = 91777425882. Its totient is φ = 91777425880.

The previous prime is 91777425833. The next prime is 91777425899. The reversal of 91777425881 is 18852477719.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79331792281 + 12445633600 = 281659^2 + 111560^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91777425881 is a prime.

It is a super-2 number, since 2×91777425881² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 91777425881.

It is not a weakly prime, because it can be changed into another prime (91777425811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45888712940 + 45888712941.

It is an arithmetic number, because the mean of its divisors is an integer number (45888712941).

Almost surely, 2^91777425881 is an apocalyptic number.

It is an amenable number.

91777425881 is a deficient number, since it is larger than the sum of its proper divisors (1).

91777425881 is an equidigital number, since it uses as much as digits as its factorization.

91777425881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7902720, while the sum is 59.

The spelling of 91777425881 in words is "ninety-one billion, seven hundred seventy-seven million, four hundred twenty-five thousand, eight hundred eighty-one".