15998840 has 64 divisors (see below), whose sum is σ = 42305760. Its totient is φ = 5368320.

The previous prime is 15998813. The next prime is 15998861. The reversal of 15998840 is 4889951.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 15998791 and 15998800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4322 + ... + 7118.

Almost surely, 2^15998840 is an apocalyptic number.

15998840 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 15998840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21152880).

15998840 is an abundant number, since it is smaller than the sum of its proper divisors (26306920).

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

15998840 is a wasteful number, since it uses less digits than its factorization.

15998840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2832 (or 2828 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 44.

The square root of 15998840 is about 3999.8549973718. The cubic root of 15998840 is about 251.9781202134.

Subtracting from 15998840 its reverse (4889951), we obtain a square (11108889 = 3333²).

The spelling of 15998840 in words is "fifteen million, nine hundred ninety-eight thousand, eight hundred forty".