2121989 has 2 divisors, whose sum is σ = 2121990. Its totient is φ = 2121988.

The previous prime is 2121979. The next prime is 2122009. The reversal of 2121989 is 9891212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1399489 + 722500 = 1183^2 + 850^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121989 - 2¹² = 2117893 is a prime.

It is a super-2 number, since 2×2121989² = 9005674632242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2121979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060994 + 1060995.

It is an arithmetic number, because the mean of its divisors is an integer number (1060995).

2^2121989 is an apocalyptic number.

It is an amenable number.

2121989 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121989 is an equidigital number, since it uses as much as digits as its factorization.

2121989 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 2121989 is about 1456.7048431305. The cubic root of 2121989 is about 128.5033282508.

The spelling of 2121989 in words is "two million, one hundred twenty-one thousand, nine hundred eighty-nine".