16712721 has 6 divisors (see below), whose sum is σ = 24140610. Its totient is φ = 11141808.

The previous prime is 16712713. The next prime is 16712741. The reversal of 16712721 is 12721761.

It can be written as a sum of positive squares in only one way, i.e., 14930496 + 1782225 = 3864^2 + 1335^2 .

It is not a de Polignac number, because 16712721 - 2³ = 16712713 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16712741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 928476 + ... + 928493.

It is an arithmetic number, because the mean of its divisors is an integer number (4023435).

Almost surely, 2^16712721 is an apocalyptic number.

It is an amenable number.

16712721 is a deficient number, since it is larger than the sum of its proper divisors (7427889).

16712721 is a wasteful number, since it uses less digits than its factorization.

16712721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1856975 (or 1856972 counting only the distinct ones).

The product of its digits is 1176, while the sum is 27.

The square root of 16712721 is about 4088.1194943397. The cubic root of 16712721 is about 255.6715402177.

The spelling of 16712721 in words is "sixteen million, seven hundred twelve thousand, seven hundred twenty-one".