2101111391 has 2 divisors, whose sum is σ = 2101111392. Its totient is φ = 2101111390.

The previous prime is 2101111381. The next prime is 2101111417. The reversal of 2101111391 is 1931111012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2101111391 - 2²² = 2096917087 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2101111301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050555695 + 1050555696.

It is an arithmetic number, because the mean of its divisors is an integer number (1050555696).

Almost surely, 2^2101111391 is an apocalyptic number.

2101111391 is a deficient number, since it is larger than the sum of its proper divisors (1).

2101111391 is an equidigital number, since it uses as much as digits as its factorization.

2101111391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54, while the sum is 20.

The square root of 2101111391 is about 45837.8816155372. The cubic root of 2101111391 is about 1280.8050337430.

The spelling of 2101111391 in words is "two billion, one hundred one million, one hundred eleven thousand, three hundred ninety-one".