16197921 has 32 divisors (see below), whose sum is σ = 25171200. Its totient is φ = 10281600.

The previous prime is 16197917. The next prime is 16197947. The reversal of 16197921 is 12979161.

16197921 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 16197921 - 2² = 16197917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16197901) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 107196 + ... + 107346.

It is an arithmetic number, because the mean of its divisors is an integer number (786600).

Almost surely, 2^16197921 is an apocalyptic number.

It is an amenable number.

16197921 is a deficient number, since it is larger than the sum of its proper divisors (8973279).

16197921 is a wasteful number, since it uses less digits than its factorization.

16197921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326 (or 320 counting only the distinct ones).

The product of its digits is 6804, while the sum is 36.

The square root of 16197921 is about 4024.6640853617. The cubic root of 16197921 is about 253.0189750749.

The spelling of 16197921 in words is "sixteen million, one hundred ninety-seven thousand, nine hundred twenty-one".