15998640 has 160 divisors (see below), whose sum is σ = 57853440. Its totient is φ = 3581952.

The previous prime is 15998629. The next prime is 15998641. The reversal of 15998640 is 4689951.

15998640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 15998592 and 15998601.

It is not an unprimeable number, because it can be changed into a prime (15998641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 149467 + ... + 149573.

It is an arithmetic number, because the mean of its divisors is an integer number (361584).

Almost surely, 2^15998640 is an apocalyptic number.

15998640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15998640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28926720).

15998640 is an abundant number, since it is smaller than the sum of its proper divisors (41854800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15998640 is a wasteful number, since it uses less digits than its factorization.

15998640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 213 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 15998640 is about 3999.8299963873. The cubic root of 15998640 is about 251.9770702241.

The spelling of 15998640 in words is "fifteen million, nine hundred ninety-eight thousand, six hundred forty".