15999972 has 12 divisors (see below), whose sum is σ = 37333296. Its totient is φ = 5333320.

The previous prime is 15999961. The next prime is 15999983. The reversal of 15999972 is 27999951.

15999972 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (15999961) and next prime (15999983).

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 666654 + ... + 666677.

It is an arithmetic number, because the mean of its divisors is an integer number (3111108).

Almost surely, 2^15999972 is an apocalyptic number.

15999972 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

15999972 is an abundant number, since it is smaller than the sum of its proper divisors (21333324).

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

15999972 is a wasteful number, since it uses less digits than its factorization.

15999972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1333338 (or 1333336 counting only the distinct ones).

The product of its digits is 459270, while the sum is 51.

The square root of 15999972 is about 3999.9964999985. The cubic root of 15999972 is about 251.9840629881.

The spelling of 15999972 in words is "fifteen million, nine hundred ninety-nine thousand, nine hundred seventy-two".