15663989 has 16 divisors (see below), whose sum is σ = 18036864. Its totient is φ = 13464000.

The previous prime is 15663979. The next prime is 15664003. The reversal of 15663989 is 98936651.

It is not a de Polignac number, because 15663989 - 2¹² = 15659893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15663929) 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, 25247 + ... + 25859.

It is an arithmetic number, because the mean of its divisors is an integer number (1127304).

Almost surely, 2^15663989 is an apocalyptic number.

It is an amenable number.

15663989 is a deficient number, since it is larger than the sum of its proper divisors (2372875).

15663989 is a wasteful number, since it uses less digits than its factorization.

15663989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 748.

The product of its digits is 349920, while the sum is 47.

The square root of 15663989 is about 3957.7757642393. The cubic root of 15663989 is about 250.2077686143.

It can be divided in two parts, 1566 and 3989, that added together give a palindrome (5555).

The spelling of 15663989 in words is "fifteen million, six hundred sixty-three thousand, nine hundred eighty-nine".