15990000 has 200 divisors, whose sum is σ = 56944272. Its totient is φ = 3840000.

The previous prime is 15989999. The next prime is 15990043. The reversal of 15990000 is 9951.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (200).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 389980 + ... + 390020.

Almost surely, 2^15990000 is an apocalyptic number.

15990000 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 15990000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28472136).

15990000 is an abundant number, since it is smaller than the sum of its proper divisors (40954272).

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

15990000 is a wasteful number, since it uses less digits than its factorization.

15990000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 405, while the sum is 24.

The square root of 15990000 is about 3998.7498046264. The cubic root of 15990000 is about 251.9317023279.

Adding to 15990000 its reverse (9951), we get a palindrome (15999951).

The spelling of 15990000 in words is "fifteen million, nine hundred ninety thousand".