91289999 has 8 divisors (see below), whose sum is σ = 94545360. Its totient is φ = 88041856.

The previous prime is 91289993. The next prime is 91290037. The reversal of 91289999 is 99998219.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91289999 is a prime.

It is a Duffinian number.

91289999 is a modest number, since divided by 9999 gives 9128 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91289993) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44024 + ... + 46050.

It is an arithmetic number, because the mean of its divisors is an integer number (11818170).

Almost surely, 2^91289999 is an apocalyptic number.

91289999 is a deficient number, since it is larger than the sum of its proper divisors (3255361).

91289999 is a wasteful number, since it uses less digits than its factorization.

91289999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3609.

The product of its digits is 944784, while the sum is 56.

The square root of 91289999 is about 9554.5800012350. The cubic root of 91289999 is about 450.2714395272.

The spelling of 91289999 in words is "ninety-one million, two hundred eighty-nine thousand, nine hundred ninety-nine".