91090121 has 4 divisors (see below), whose sum is σ = 94028544. Its totient is φ = 88151700.

The previous prime is 91090099. The next prime is 91090127. The reversal of 91090121 is 12109019.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91090121 - 2¹⁸ = 90827977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91090127) 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, 1469165 + ... + 1469226.

It is an arithmetic number, because the mean of its divisors is an integer number (23507136).

Almost surely, 2^91090121 is an apocalyptic number.

It is an amenable number.

91090121 is a deficient number, since it is larger than the sum of its proper divisors (2938423).

91090121 is a wasteful number, since it uses less digits than its factorization.

91090121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2938422.

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 91090121 is about 9544.1144691375. The cubic root of 91090121 is about 449.9425786814.

The spelling of 91090121 in words is "ninety-one million, ninety thousand, one hundred twenty-one".