91028139 has 8 divisors (see below), whose sum is σ = 122327040. Its totient is φ = 60207336.

The previous prime is 91028137. The next prime is 91028141. The reversal of 91028139 is 93182019.

It is an interprime number because it is at equal distance from previous prime (91028137) and next prime (91028141).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 91028139 - 2¹ = 91028137 is a prime.

It is a super-2 number, since 2×91028139² = 16572244179606642, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (91028131) 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 in 7 ways as a sum of consecutive naturals, for example, 119079 + ... + 119840.

It is an arithmetic number, because the mean of its divisors is an integer number (15290880).

Almost surely, 2^91028139 is an apocalyptic number.

91028139 is a deficient number, since it is larger than the sum of its proper divisors (31298901).

91028139 is a wasteful number, since it uses less digits than its factorization.

91028139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239049.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 91028139 is about 9540.8667845223. The cubic root of 91028139 is about 449.8405014985.

The spelling of 91028139 in words is "ninety-one million, twenty-eight thousand, one hundred thirty-nine".