91231863 has 16 divisors (see below), whose sum is σ = 128369280. Its totient is φ = 57474144.

The previous prime is 91231859. The next prime is 91231867. The reversal of 91231863 is 36813219.

It is an interprime number because it is at equal distance from previous prime (91231859) and next prime (91231867).

It is not a de Polignac number, because 91231863 - 2² = 91231859 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91231867) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23445 + ... + 27057.

It is an arithmetic number, because the mean of its divisors is an integer number (8023080).

Almost surely, 2^91231863 is an apocalyptic number.

91231863 is a deficient number, since it is larger than the sum of its proper divisors (37137417).

91231863 is a wasteful number, since it uses less digits than its factorization.

91231863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4078.

The product of its digits is 7776, while the sum is 33.

The square root of 91231863 is about 9551.5372061255. The cubic root of 91231863 is about 450.1758374554.

The spelling of 91231863 in words is "ninety-one million, two hundred thirty-one thousand, eight hundred sixty-three".