2101220091 has 24 divisors (see below), whose sum is σ = 3090932624. Its totient is φ = 1375133760.

The previous prime is 2101220087. The next prime is 2101220167. The reversal of 2101220091 is 1900221012.

It is not a de Polignac number, because 2101220091 - 2² = 2101220087 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2101220081) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 296805 + ... + 303801.

Almost surely, 2^2101220091 is an apocalyptic number.

2101220091 is a deficient number, since it is larger than the sum of its proper divisors (989712533).

2101220091 is a wasteful number, since it uses less digits than its factorization.

2101220091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7611 (or 7608 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 2101220091 is about 45839.0673007207. The cubic root of 2101220091 is about 1280.8271206422.

The spelling of 2101220091 in words is "two billion, one hundred one million, two hundred twenty thousand, ninety-one".