2128991 has 2 divisors, whose sum is σ = 2128992. Its totient is φ = 2128990.

The previous prime is 2128963. The next prime is 2128993. The reversal of 2128991 is 1998212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2128991 - 2¹⁰ = 2127967 is a prime.

Together with 2128993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2128993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1064495 + 1064496.

It is an arithmetic number, because the mean of its divisors is an integer number (1064496).

2^2128991 is an apocalyptic number.

2128991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2128991 is an equidigital number, since it uses as much as digits as its factorization.

2128991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 32.

The square root of 2128991 is about 1459.1062332812. The cubic root of 2128991 is about 128.6445153534.

The spelling of 2128991 in words is "two million, one hundred twenty-eight thousand, nine hundred ninety-one".