90999091 has 4 divisors (see below), whose sum is σ = 91024312. Its totient is φ = 90973872.

The previous prime is 90999059. The next prime is 90999101. The reversal of 90999091 is 19099909.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19099909 = 79 ⋅241771.

It is a cyclic number.

It is not a de Polignac number, because 90999091 - 2⁵ = 90999059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90990091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6066 + ... + 14791.

It is an arithmetic number, because the mean of its divisors is an integer number (22756078).

Almost surely, 2^90999091 is an apocalyptic number.

90999091 is a deficient number, since it is larger than the sum of its proper divisors (25221).

90999091 is a wasteful number, since it uses less digits than its factorization.

90999091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25220.

The product of its (nonzero) digits is 59049, while the sum is 46.

The square root of 90999091 is about 9539.3443695046. The cubic root of 90999091 is about 449.7926468563.

It can be divided in two parts, 909 and 99091, that added together give a 5-th power (100000 = 10⁵).

The spelling of 90999091 in words is "ninety million, nine hundred ninety-nine thousand, ninety-one".