15561985 has 8 divisors (see below), whose sum is σ = 18758016. Its totient is φ = 12393840.

The previous prime is 15561983. The next prime is 15561989. The reversal of 15561985 is 58916551.

15561985 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 15561985 - 2¹ = 15561983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15561983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5721 + ... + 7990.

It is an arithmetic number, because the mean of its divisors is an integer number (2344752).

Almost surely, 2^15561985 is an apocalyptic number.

It is an amenable number.

15561985 is a deficient number, since it is larger than the sum of its proper divisors (3196031).

15561985 is a wasteful number, since it uses less digits than its factorization.

15561985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13943.

The product of its digits is 54000, while the sum is 40.

The square root of 15561985 is about 3944.8681853770. The cubic root of 15561985 is about 249.6634671859.

The spelling of 15561985 in words is "fifteen million, five hundred sixty-one thousand, nine hundred eighty-five".