91912789 has 4 divisors (see below), whose sum is σ = 93020256. Its totient is φ = 90805324.

The previous prime is 91912783. The next prime is 91912813. The reversal of 91912789 is 98721919.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 98721919 = 4409 ⋅22391.

It is a cyclic number.

It is not a de Polignac number, because 91912789 - 2¹⁵ = 91880021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91912783) 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, 553609 + ... + 553774.

It is an arithmetic number, because the mean of its divisors is an integer number (23255064).

Almost surely, 2^91912789 is an apocalyptic number.

It is an amenable number.

91912789 is a deficient number, since it is larger than the sum of its proper divisors (1107467).

91912789 is a wasteful number, since it uses less digits than its factorization.

91912789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1107466.

The product of its digits is 81648, while the sum is 46.

The square root of 91912789 is about 9587.1157810887. The cubic root of 91912789 is about 451.2930529335.

The spelling of 91912789 in words is "ninety-one million, nine hundred twelve thousand, seven hundred eighty-nine".