1397989 has 2 divisors, whose sum is σ = 1397990. Its totient is φ = 1397988.

The previous prime is 1397983. The next prime is 1397999. The reversal of 1397989 is 9897931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1361889 + 36100 = 1167^2 + 190^2 .

It is an emirp because it is prime and its reverse (9897931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1397989 - 2⁷ = 1397861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1397983) 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, 698994 + 698995.

It is an arithmetic number, because the mean of its divisors is an integer number (698995).

2^1397989 is an apocalyptic number.

It is an amenable number.

1397989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1397989 is an equidigital number, since it uses as much as digits as its factorization.

1397989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 122472, while the sum is 46.

The square root of 1397989 is about 1182.3658486272. The cubic root of 1397989 is about 111.8153046488.

It can be divided in two parts, 139 and 7989, that added together give a triangular number (8128 = T₁₂₇).

The spelling of 1397989 in words is "one million, three hundred ninety-seven thousand, nine hundred eighty-nine".