1947989 has 2 divisors, whose sum is σ = 1947990. Its totient is φ = 1947988.

The previous prime is 1947983. The next prime is 1947991. The reversal of 1947989 is 9897491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1030225 + 917764 = 1015^2 + 958^2 .

It is a cyclic number.

It is not a de Polignac number, because 1947989 - 2⁴ = 1947973 is a prime.

It is a super-2 number, since 2×1947989² = 7589322288242, which contains 22 as substring.

Together with 1947991, 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 (1947983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 973994 + 973995.

It is an arithmetic number, because the mean of its divisors is an integer number (973995).

2^1947989 is an apocalyptic number.

It is an amenable number.

1947989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1947989 is an equidigital number, since it uses as much as digits as its factorization.

1947989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 47.

The square root of 1947989 is about 1395.7037651307. The cubic root of 1947989 is about 124.8903358183.

The spelling of 1947989 in words is "one million, nine hundred forty-seven thousand, nine hundred eighty-nine".