2120111991 has 24 divisors (see below), whose sum is σ = 3098210544. Its totient is φ = 1396961280.

The previous prime is 2120111923. The next prime is 2120111993. The reversal of 2120111991 is 1991110212.

It is not a de Polignac number, because 2120111991 - 2¹⁹ = 2119587703 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2120111993) 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, 299505 + ... + 306501.

It is an arithmetic number, because the mean of its divisors is an integer number (129092106).

Almost surely, 2^2120111991 is an apocalyptic number.

2120111991 is a deficient number, since it is larger than the sum of its proper divisors (978098553).

2120111991 is a wasteful number, since it uses less digits than its factorization.

2120111991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7391 (or 7388 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 27.

The square root of 2120111991 is about 46044.6738613708. The cubic root of 2120111991 is about 1284.6542779406.

The spelling of 2120111991 in words is "two billion, one hundred twenty million, one hundred eleven thousand, nine hundred ninety-one".