91000639 has 2 divisors, whose sum is σ = 91000640. Its totient is φ = 91000638.

The previous prime is 91000589. The next prime is 91000661. The reversal of 91000639 is 93600019.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91000639 is a prime.

It is a super-2 number, since 2×91000639² = 16562232596816642, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91000669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45500319 + 45500320.

It is an arithmetic number, because the mean of its divisors is an integer number (45500320).

Almost surely, 2^91000639 is an apocalyptic number.

91000639 is a deficient number, since it is larger than the sum of its proper divisors (1).

91000639 is an equidigital number, since it uses as much as digits as its factorization.

91000639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 91000639 is about 9539.4255068112. The cubic root of 91000639 is about 449.7951973399.

The spelling of 91000639 in words is "ninety-one million, six hundred thirty-nine", and thus it is an aban number.