15999920 has 20 divisors (see below), whose sum is σ = 37200000. Its totient is φ = 6399936.

The previous prime is 15999883. The next prime is 15999923. The reversal of 15999920 is 2999951.

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (15999923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99920 + ... + 100079.

It is an arithmetic number, because the mean of its divisors is an integer number (1860000).

Almost surely, 2^15999920 is an apocalyptic number.

15999920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15999920 is an abundant number, since it is smaller than the sum of its proper divisors (21200080).

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

15999920 is a wasteful number, since it uses less digits than its factorization.

15999920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200012 (or 200006 counting only the distinct ones).

The product of its (nonzero) digits is 65610, while the sum is 44.

The square root of 15999920 is about 3999.9899999875. The cubic root of 15999920 is about 251.9837900046.

The spelling of 15999920 in words is "fifteen million, nine hundred ninety-nine thousand, nine hundred twenty".