15991920 has 240 divisors, whose sum is σ = 64995840. Its totient is φ = 3442176.

The previous prime is 15991909. The next prime is 15991933. The reversal of 15991920 is 2919951.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 95677 + ... + 95843.

It is an arithmetic number, because the mean of its divisors is an integer number (270816).

Almost surely, 2^15991920 is an apocalyptic number.

15991920 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 15991920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32497920).

15991920 is an abundant number, since it is smaller than the sum of its proper divisors (49003920).

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

15991920 is a wasteful number, since it uses less digits than its factorization.

15991920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 7290, while the sum is 36.

The square root of 15991920 is about 3998.9898724553. The cubic root of 15991920 is about 251.9417854947.

The spelling of 15991920 in words is "fifteen million, nine hundred ninety-one thousand, nine hundred twenty".