1289921 has 2 divisors, whose sum is σ = 1289922. Its totient is φ = 1289920.

The previous prime is 1289881. The next prime is 1289927. The reversal of 1289921 is 1299821.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 748225 + 541696 = 865^2 + 736^2 .

It is an emirp because it is prime and its reverse (1299821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1289921 - 2¹⁸ = 1027777 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1289927) 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, 644960 + 644961.

It is an arithmetic number, because the mean of its divisors is an integer number (644961).

2^1289921 is an apocalyptic number.

It is an amenable number.

1289921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1289921 is an equidigital number, since it uses as much as digits as its factorization.

1289921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 32.

The square root of 1289921 is about 1135.7468908168. The cubic root of 1289921 is about 108.8565011193.

The spelling of 1289921 in words is "one million, two hundred eighty-nine thousand, nine hundred twenty-one".