15553985 has 4 divisors (see below), whose sum is σ = 18664788. Its totient is φ = 12443184.

The previous prime is 15553981. The next prime is 15553987. The reversal of 15553985 is 58935551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58935551 = 97 ⋅607583.

It can be written as a sum of positive squares in 2 ways, for example, as 7579009 + 7974976 = 2753^2 + 2824^2 .

It is a cyclic number.

It is not a de Polignac number, because 15553985 - 2² = 15553981 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15553981) 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 in 3 ways as a sum of consecutive naturals, for example, 1555394 + ... + 1555403.

It is an arithmetic number, because the mean of its divisors is an integer number (4666197).

Almost surely, 2^15553985 is an apocalyptic number.

It is an amenable number.

15553985 is a deficient number, since it is larger than the sum of its proper divisors (3110803).

15553985 is an equidigital number, since it uses as much as digits as its factorization.

15553985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3110802.

The product of its digits is 135000, while the sum is 41.

The square root of 15553985 is about 3943.8540794507. The cubic root of 15553985 is about 249.6206780840.

The spelling of 15553985 in words is "fifteen million, five hundred fifty-three thousand, nine hundred eighty-five".