16091921 has 4 divisors (see below), whose sum is σ = 16182000. Its totient is φ = 16001844.

The previous prime is 16091899. The next prime is 16091923. The reversal of 16091921 is 12919061.

16091921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16091921 - 2⁶ = 16091857 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16091923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44771 + ... + 45128.

It is an arithmetic number, because the mean of its divisors is an integer number (4045500).

Almost surely, 2^16091921 is an apocalyptic number.

It is an amenable number.

16091921 is a deficient number, since it is larger than the sum of its proper divisors (90079).

16091921 is an equidigital number, since it uses as much as digits as its factorization.

16091921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90078.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 16091921 is about 4011.4736693639. The cubic root of 16091921 is about 252.4658438261.

The spelling of 16091921 in words is "sixteen million, ninety-one thousand, nine hundred twenty-one".