15981009 has 16 divisors (see below), whose sum is σ = 23395584. Its totient is φ = 9622800.

The previous prime is 15980999. The next prime is 15981013. The reversal of 15981009 is 90018951.

It is not a de Polignac number, because 15981009 - 2²⁰ = 14932433 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (15981019) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3894 + ... + 6864.

It is an arithmetic number, because the mean of its divisors is an integer number (1462224).

Almost surely, 2^15981009 is an apocalyptic number.

It is an amenable number.

15981009 is a deficient number, since it is larger than the sum of its proper divisors (7414575).

15981009 is a wasteful number, since it uses less digits than its factorization.

15981009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3148.

The product of its (nonzero) digits is 3240, while the sum is 33.

The square root of 15981009 is about 3997.6254201713. The cubic root of 15981009 is about 251.8844740057.

The spelling of 15981009 in words is "fifteen million, nine hundred eighty-one thousand, nine".