90690191 has 4 divisors (see below), whose sum is σ = 91299000. Its totient is φ = 90081384.

The previous prime is 90690181. The next prime is 90690203. The reversal of 90690191 is 19109609.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19109609 = 31 ⋅616439.

It is a cyclic number.

It is not a de Polignac number, because 90690191 - 2²² = 86495887 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 (90690151) 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, 304181 + ... + 304478.

It is an arithmetic number, because the mean of its divisors is an integer number (22824750).

Almost surely, 2^90690191 is an apocalyptic number.

90690191 is a deficient number, since it is larger than the sum of its proper divisors (608809).

90690191 is a wasteful number, since it uses less digits than its factorization.

90690191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 608808.

The product of its (nonzero) digits is 4374, while the sum is 35.

The square root of 90690191 is about 9523.1397658545. The cubic root of 90690191 is about 449.2831236009.

The spelling of 90690191 in words is "ninety million, six hundred ninety thousand, one hundred ninety-one".