91770121 has 4 divisors (see below), whose sum is σ = 91861200. Its totient is φ = 91679044.

The previous prime is 91770103. The next prime is 91770139. The reversal of 91770121 is 12107719.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12107719 = 13 ⋅931363.

It is an interprime number because it is at equal distance from previous prime (91770103) and next prime (91770139).

It is a cyclic number.

It is not a de Polignac number, because 91770121 - 2⁵ = 91770089 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91770121.

It is not an unprimeable number, because it can be changed into a prime (91770221) 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, 44011 + ... + 46048.

It is an arithmetic number, because the mean of its divisors is an integer number (22965300).

Almost surely, 2^91770121 is an apocalyptic number.

It is an amenable number.

91770121 is a deficient number, since it is larger than the sum of its proper divisors (91079).

91770121 is a wasteful number, since it uses less digits than its factorization.

91770121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91078.

The product of its (nonzero) digits is 882, while the sum is 28.

The square root of 91770121 is about 9579.6722804071. The cubic root of 91770121 is about 451.0594314038.

The spelling of 91770121 in words is "ninety-one million, seven hundred seventy thousand, one hundred twenty-one".