91239749 has 2 divisors, whose sum is σ = 91239750. Its totient is φ = 91239748.

The previous prime is 91239677. The next prime is 91239751. The reversal of 91239749 is 94793219.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91202500 + 37249 = 9550^2 + 193^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91239749 is a prime.

It is a Sophie Germain prime.

Together with 91239751, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91239779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45619874 + 45619875.

It is an arithmetic number, because the mean of its divisors is an integer number (45619875).

Almost surely, 2^91239749 is an apocalyptic number.

It is an amenable number.

91239749 is a deficient number, since it is larger than the sum of its proper divisors (1).

91239749 is an equidigital number, since it uses as much as digits as its factorization.

91239749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 44.

The square root of 91239749 is about 9551.9500103382. The cubic root of 91239749 is about 450.1888080129.

The spelling of 91239749 in words is "ninety-one million, two hundred thirty-nine thousand, seven hundred forty-nine".