15899994 has 48 divisors (see below), whose sum is σ = 37930464. Its totient is φ = 4773600.

The previous prime is 15899987. The next prime is 15899999. The reversal of 15899994 is 49999851.

It is a self number, because there is not a number n which added to its sum of digits gives 15899994.

It is not an unprimeable number, because it can be changed into a prime (15899999) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25632 + ... + 26244.

It is an arithmetic number, because the mean of its divisors is an integer number (790218).

Almost surely, 2^15899994 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15899994, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18965232).

15899994 is an abundant number, since it is smaller than the sum of its proper divisors (22030470).

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

15899994 is a wasteful number, since it uses less digits than its factorization.

15899994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 763 (or 760 counting only the distinct ones).

The product of its digits is 1049760, while the sum is 54.

The square root of 15899994 is about 3987.4796551205. The cubic root of 15899994 is about 251.4581137500.

It can be divided in two parts, 15 and 899994, that added together give a palindrome (900009).

The spelling of 15899994 in words is "fifteen million, eight hundred ninety-nine thousand, nine hundred ninety-four".