90640091 has 4 divisors (see below), whose sum is σ = 91916784. Its totient is φ = 89363400.

The previous prime is 90640061. The next prime is 90640117. The reversal of 90640091 is 19004609.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 90640091 - 2²² = 86445787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90640031) 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, 638240 + ... + 638381.

It is an arithmetic number, because the mean of its divisors is an integer number (22979196).

Almost surely, 2^90640091 is an apocalyptic number.

90640091 is a deficient number, since it is larger than the sum of its proper divisors (1276693).

90640091 is a wasteful number, since it uses less digits than its factorization.

90640091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1276692.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 90640091 is about 9520.5089674870. The cubic root of 90640091 is about 449.2003758402.

The spelling of 90640091 in words is "ninety million, six hundred forty thousand, ninety-one".