1549921 has 2 divisors, whose sum is σ = 1549922. Its totient is φ = 1549920.

The previous prime is 1549897. The next prime is 1549931. The reversal of 1549921 is 1299451.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1537600 + 12321 = 1240^2 + 111^2 .

It is an emirp because it is prime and its reverse (1299451) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1549921 - 2⁹ = 1549409 is a prime.

It is not a weakly prime, because it can be changed into another prime (1549931) 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, 774960 + 774961.

It is an arithmetic number, because the mean of its divisors is an integer number (774961).

2^1549921 is an apocalyptic number.

It is an amenable number.

1549921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1549921 is an equidigital number, since it uses as much as digits as its factorization.

1549921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 31.

The square root of 1549921 is about 1244.9582322311. The cubic root of 1549921 is about 115.7274865366.

The spelling of 1549921 in words is "one million, five hundred forty-nine thousand, nine hundred twenty-one".