91868431 has 2 divisors, whose sum is σ = 91868432. Its totient is φ = 91868430.

The previous prime is 91868429. The next prime is 91868437. The reversal of 91868431 is 13486819.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91868431 - 2¹ = 91868429 is a prime.

It is a super-2 number, since 2×91868431² = 16879617228803522, which contains 22 as substring.

Together with 91868429, 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 (91868437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45934215 + 45934216.

It is an arithmetic number, because the mean of its divisors is an integer number (45934216).

Almost surely, 2^91868431 is an apocalyptic number.

91868431 is a deficient number, since it is larger than the sum of its proper divisors (1).

91868431 is an equidigital number, since it uses as much as digits as its factorization.

91868431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 40.

The square root of 91868431 is about 9584.8020845503. The cubic root of 91868431 is about 451.2204417887.

The spelling of 91868431 in words is "ninety-one million, eight hundred sixty-eight thousand, four hundred thirty-one".