2100121999 has 2 divisors, whose sum is σ = 2100122000. Its totient is φ = 2100121998.

The previous prime is 2100121997. The next prime is 2100122039. The reversal of 2100121999 is 9991210012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2100121999 - 2¹ = 2100121997 is a prime.

Together with 2100121997, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2100121997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050060999 + 1050061000.

It is an arithmetic number, because the mean of its divisors is an integer number (1050061000).

Almost surely, 2^2100121999 is an apocalyptic number.

2100121999 is a deficient number, since it is larger than the sum of its proper divisors (1).

2100121999 is an equidigital number, since it uses as much as digits as its factorization.

2100121999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 34.

The square root of 2100121999 is about 45827.0880484458. The cubic root of 2100121999 is about 1280.6039628212.

The spelling of 2100121999 in words is "two billion, one hundred million, one hundred twenty-one thousand, nine hundred ninety-nine".