2157989 has 2 divisors, whose sum is σ = 2157990. Its totient is φ = 2157988.

The previous prime is 2157923. The next prime is 2158019. The reversal of 2157989 is 9897512.

2157989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1464100 + 693889 = 1210^2 + 833^2 .

It is a cyclic number.

It is not a de Polignac number, because 2157989 - 2⁸ = 2157733 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2153989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078994 + 1078995.

It is an arithmetic number, because the mean of its divisors is an integer number (1078995).

2^2157989 is an apocalyptic number.

It is an amenable number.

2157989 is a deficient number, since it is larger than the sum of its proper divisors (1).

2157989 is an equidigital number, since it uses as much as digits as its factorization.

2157989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45360, while the sum is 41.

The square root of 2157989 is about 1469.0095302618. The cubic root of 2157989 is about 129.2259525739.

The spelling of 2157989 in words is "two million, one hundred fifty-seven thousand, nine hundred eighty-nine".