91939 has 2 divisors, whose sum is σ = 91940. Its totient is φ = 91938.

The previous prime is 91921. The next prime is 91943. The reversal of 91939 is 93919.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91939 - 2⁷ = 91811 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91939.

It is not a weakly prime, because it can be changed into another prime (91909) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45969 + 45970.

It is an arithmetic number, because the mean of its divisors is an integer number (45970).

2⁹¹⁹³⁹ is an apocalyptic number.

91939 is a deficient number, since it is larger than the sum of its proper divisors (1).

91939 is an equidigital number, since it uses as much as digits as its factorization.

91939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2187, while the sum is 31.

The square root of 91939 is about 303.2144455662. The cubic root of 91939 is about 45.1335947646.

The spelling of 91939 in words is "ninety-one thousand, nine hundred thirty-nine".