90691391 has 4 divisors (see below), whose sum is σ = 103647312. Its totient is φ = 77735472.

The previous prime is 90691373. The next prime is 90691453. The reversal of 90691391 is 19319609.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90691391 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 (90691291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6477950 + ... + 6477963.

It is an arithmetic number, because the mean of its divisors is an integer number (25911828).

Almost surely, 2^90691391 is an apocalyptic number.

90691391 is a deficient number, since it is larger than the sum of its proper divisors (12955921).

90691391 is a wasteful number, since it uses less digits than its factorization.

90691391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12955920.

The product of its (nonzero) digits is 13122, while the sum is 38.

The square root of 90691391 is about 9523.2027700769. The cubic root of 90691391 is about 449.2851052094.

The spelling of 90691391 in words is "ninety million, six hundred ninety-one thousand, three hundred ninety-one".