16045721 has 4 divisors (see below), whose sum is σ = 16226100. Its totient is φ = 15865344.

The previous prime is 16045717. The next prime is 16045741. The reversal of 16045721 is 12754061.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12754061 = 47 ⋅271363.

It can be written as a sum of positive squares in 2 ways, for example, as 8620096 + 7425625 = 2936^2 + 2725^2 .

It is a cyclic number.

It is not a de Polignac number, because 16045721 - 2² = 16045717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16045741) 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, 90056 + ... + 90233.

It is an arithmetic number, because the mean of its divisors is an integer number (4056525).

Almost surely, 2^16045721 is an apocalyptic number.

It is an amenable number.

16045721 is a deficient number, since it is larger than the sum of its proper divisors (180379).

16045721 is an equidigital number, since it uses as much as digits as its factorization.

16045721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180378.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 16045721 is about 4005.7110479914. The cubic root of 16045721 is about 252.2240019267.

Adding to 16045721 its reverse (12754061), we get a palindrome (28799782).

The spelling of 16045721 in words is "sixteen million, forty-five thousand, seven hundred twenty-one".