1553985 has 24 divisors (see below), whose sum is σ = 2795520. Its totient is φ = 828144.

The previous prime is 1553983. The next prime is 1554019. The reversal of 1553985 is 5893551.

It is a happy number.

It is not a de Polignac number, because 1553985 - 2¹ = 1553983 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1553983) 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 in 23 ways as a sum of consecutive naturals, for example, 576 + ... + 1854.

It is an arithmetic number, because the mean of its divisors is an integer number (116480).

2^1553985 is an apocalyptic number.

1553985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1553985 is a deficient number, since it is larger than the sum of its proper divisors (1241535).

1553985 is an equidigital number, since it uses as much as digits as its factorization.

1553985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1299 (or 1287 counting only the distinct ones).

The product of its digits is 27000, while the sum is 36.

The square root of 1553985 is about 1246.5893469784. The cubic root of 1553985 is about 115.8285467488.

It can be divided in two parts, 155398 and 5, that added together give a triangular number (155403 = T₅₅₇).

The spelling of 1553985 in words is "one million, five hundred fifty-three thousand, nine hundred eighty-five".