1971889 has 2 divisors, whose sum is σ = 1971890. Its totient is φ = 1971888.

The previous prime is 1971887. The next prime is 1971901. The reversal of 1971889 is 9881791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1937664 + 34225 = 1392^2 + 185^2 .

It is a cyclic number.

It is not a de Polignac number, because 1971889 - 2¹ = 1971887 is a prime.

Together with 1971887, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1971887) 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, 985944 + 985945.

It is an arithmetic number, because the mean of its divisors is an integer number (985945).

2^1971889 is an apocalyptic number.

It is an amenable number.

1971889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1971889 is an equidigital number, since it uses as much as digits as its factorization.

1971889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 43.

The square root of 1971889 is about 1404.2396519113. The cubic root of 1971889 is about 125.3990235529.

The spelling of 1971889 in words is "one million, nine hundred seventy-one thousand, eight hundred eighty-nine".