1550999 has 2 divisors, whose sum is σ = 1551000. Its totient is φ = 1550998.

The previous prime is 1550993. The next prime is 1551001. The reversal of 1550999 is 9990551.

It is a strong prime.

It is an emirp because it is prime and its reverse (9990551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1550999 - 2¹² = 1546903 is a prime.

It is a Sophie Germain prime.

Together with 1551001, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1550993) 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, 775499 + 775500.

It is an arithmetic number, because the mean of its divisors is an integer number (775500).

2^1550999 is an apocalyptic number.

1550999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1550999 is an equidigital number, since it uses as much as digits as its factorization.

1550999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18225, while the sum is 38.

The square root of 1550999 is about 1245.3911032282. The cubic root of 1550999 is about 115.7543105529.

The spelling of 1550999 in words is "one million, five hundred fifty thousand, nine hundred ninety-nine".