16107721 has 24 divisors (see below), whose sum is σ = 20228616. Its totient is φ = 12741120.

The previous prime is 16107719. The next prime is 16107739. The reversal of 16107721 is 12770161.

It can be written as a sum of positive squares in 4 ways, for example, as 19600 + 16088121 = 140^2 + 4011^2 .

It is not a de Polignac number, because 16107721 - 2¹ = 16107719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16107701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 50655 + ... + 50971.

It is an arithmetic number, because the mean of its divisors is an integer number (842859).

Almost surely, 2^16107721 is an apocalyptic number.

It is an amenable number.

16107721 is a deficient number, since it is larger than the sum of its proper divisors (4120895).

16107721 is a wasteful number, since it uses less digits than its factorization.

16107721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409 (or 402 counting only the distinct ones).

The product of its (nonzero) digits is 588, while the sum is 25.

The square root of 16107721 is about 4013.4425372740. The cubic root of 16107721 is about 252.5484454312.

Adding to 16107721 its reverse (12770161), we get a palindrome (28877882).

The spelling of 16107721 in words is "sixteen million, one hundred seven thousand, seven hundred twenty-one".