91408288381 has 2 divisors, whose sum is σ = 91408288382. Its totient is φ = 91408288380.

The previous prime is 91408288379. The next prime is 91408288399. The reversal of 91408288381 is 18388280419.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81829751481 + 9578536900 = 286059^2 + 97870^2 .

It is a cyclic number.

It is not a de Polignac number, because 91408288381 - 2¹ = 91408288379 is a prime.

It is a super-2 number, since 2×91408288381² (a number of 23 digits) contains 22 as substring.

Together with 91408288379, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91408286381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45704144190 + 45704144191.

It is an arithmetic number, because the mean of its divisors is an integer number (45704144191).

Almost surely, 2^91408288381 is an apocalyptic number.

It is an amenable number.

91408288381 is a deficient number, since it is larger than the sum of its proper divisors (1).

91408288381 is an equidigital number, since it uses as much as digits as its factorization.

91408288381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 884736, while the sum is 52.

The spelling of 91408288381 in words is "ninety-one billion, four hundred eight million, two hundred eighty-eight thousand, three hundred eighty-one".