15996921 has 8 divisors (see below), whose sum is σ = 21403200. Its totient is φ = 10627632.

The previous prime is 15996889. The next prime is 15996923. The reversal of 15996921 is 12969951.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 15996921 - 2⁵ = 15996889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15996923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8221 + ... + 9978.

It is an arithmetic number, because the mean of its divisors is an integer number (2675400).

Almost surely, 2^15996921 is an apocalyptic number.

It is an amenable number.

15996921 is a deficient number, since it is larger than the sum of its proper divisors (5406279).

15996921 is a wasteful number, since it uses less digits than its factorization.

15996921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18495.

The product of its digits is 43740, while the sum is 42.

The square root of 15996921 is about 3999.6151064821. The cubic root of 15996921 is about 251.9680452049.

The spelling of 15996921 in words is "fifteen million, nine hundred ninety-six thousand, nine hundred twenty-one".