2121191191 has 4 divisors (see below), whose sum is σ = 2424218512. Its totient is φ = 1818163872.

The previous prime is 2121191173. The next prime is 2121191197. The reversal of 2121191191 is 1911911212.

It is a happy number.

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

It is not a de Polignac number, because 2121191191 - 2⁷ = 2121191063 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 (2121191197) 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, 151513650 + ... + 151513663.

It is an arithmetic number, because the mean of its divisors is an integer number (606054628).

Almost surely, 2^2121191191 is an apocalyptic number.

2121191191 is a deficient number, since it is larger than the sum of its proper divisors (303027321).

2121191191 is an equidigital number, since it uses as much as digits as its factorization.

2121191191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303027320.

The product of its digits is 324, while the sum is 28.

The square root of 2121191191 is about 46056.3914239924. The cubic root of 2121191191 is about 1284.8722166988.

The spelling of 2121191191 in words is "two billion, one hundred twenty-one million, one hundred ninety-one thousand, one hundred ninety-one".