3989021 has 2 divisors, whose sum is σ = 3989022. Its totient is φ = 3989020.

The previous prime is 3989009. The next prime is 3989023. The reversal of 3989021 is 1209893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2524921 + 1464100 = 1589^2 + 1210^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3989021 is a prime.

Together with 3989023, 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 (3989023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1994510 + 1994511.

It is an arithmetic number, because the mean of its divisors is an integer number (1994511).

Almost surely, 2^3989021 is an apocalyptic number.

It is an amenable number.

3989021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3989021 is an equidigital number, since it uses as much as digits as its factorization.

3989021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 3989021 is about 1997.2533639977. The cubic root of 3989021 is about 158.5947381489.

The spelling of 3989021 in words is "three million, nine hundred eighty-nine thousand, twenty-one".