16128921 has 8 divisors (see below), whose sum is σ = 21602560. Its totient is φ = 10703952.

The previous prime is 16128887. The next prime is 16128941. The reversal of 16128921 is 12982161.

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 16128921 - 2¹⁰ = 16127897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16128941) 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, 11386 + ... + 12723.

It is an arithmetic number, because the mean of its divisors is an integer number (2700320).

Almost surely, 2^16128921 is an apocalyptic number.

It is an amenable number.

16128921 is a deficient number, since it is larger than the sum of its proper divisors (5473639).

16128921 is a wasteful number, since it uses less digits than its factorization.

16128921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24335.

The product of its digits is 1728, while the sum is 30.

The square root of 16128921 is about 4016.0827929713. The cubic root of 16128921 is about 252.6591931461.

The spelling of 16128921 in words is "sixteen million, one hundred twenty-eight thousand, nine hundred twenty-one".