91086989 has 4 divisors (see below), whose sum is σ = 104099424. Its totient is φ = 78074556.

The previous prime is 91086979. The next prime is 91086997. The reversal of 91086989 is 98968019.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 91086989 - 2⁸ = 91086733 is a prime.

It is a super-2 number, since 2×91086989² = 16593679130172242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91086979) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6506207 + ... + 6506220.

It is an arithmetic number, because the mean of its divisors is an integer number (26024856).

Almost surely, 2^91086989 is an apocalyptic number.

It is an amenable number.

91086989 is a deficient number, since it is larger than the sum of its proper divisors (13012435).

91086989 is a wasteful number, since it uses less digits than its factorization.

91086989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13012434.

The product of its (nonzero) digits is 279936, while the sum is 50.

The square root of 91086989 is about 9543.9503875492. The cubic root of 91086989 is about 449.9374217508.

The spelling of 91086989 in words is "ninety-one million, eighty-six thousand, nine hundred eighty-nine".