16125721 has 2 divisors, whose sum is σ = 16125722. Its totient is φ = 16125720.

The previous prime is 16125689. The next prime is 16125749. The reversal of 16125721 is 12752161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15721225 + 404496 = 3965^2 + 636^2 .

It is a cyclic number.

It is not a de Polignac number, because 16125721 - 2⁵ = 16125689 is a prime.

It is not a weakly prime, because it can be changed into another prime (16125521) 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 as a sum of consecutive naturals, namely, 8062860 + 8062861.

It is an arithmetic number, because the mean of its divisors is an integer number (8062861).

Almost surely, 2^16125721 is an apocalyptic number.

It is an amenable number.

16125721 is a deficient number, since it is larger than the sum of its proper divisors (1).

16125721 is an equidigital number, since it uses as much as digits as its factorization.

16125721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 840, while the sum is 25.

The square root of 16125721 is about 4015.6843750474. The cubic root of 16125721 is about 252.6424827310.

Adding to 16125721 its reverse (12752161), we get a palindrome (28877882).

The spelling of 16125721 in words is "sixteen million, one hundred twenty-five thousand, seven hundred twenty-one".