1551985 has 4 divisors (see below), whose sum is σ = 1862388. Its totient is φ = 1241584.

The previous prime is 1551967. The next prime is 1551997. The reversal of 1551985 is 5891551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5891551 = 1009 ⋅5839.

It can be written as a sum of positive squares in 2 ways, for example, as 1100401 + 451584 = 1049^2 + 672^2 .

It is a cyclic number.

It is not a de Polignac number, because 1551985 - 2¹¹ = 1549937 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1551985.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 155194 + ... + 155203.

It is an arithmetic number, because the mean of its divisors is an integer number (465597).

2^1551985 is an apocalyptic number.

It is an amenable number.

1551985 is a deficient number, since it is larger than the sum of its proper divisors (310403).

1551985 is an equidigital number, since it uses as much as digits as its factorization.

1551985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310402.

The product of its digits is 9000, while the sum is 34.

The square root of 1551985 is about 1245.7868999151. The cubic root of 1551985 is about 115.7788344400.

The spelling of 1551985 in words is "one million, five hundred fifty-one thousand, nine hundred eighty-five".