16396721 has 8 divisors (see below), whose sum is σ = 18939744. Its totient is φ = 14029120.

The previous prime is 16396711. The next prime is 16396741. The reversal of 16396721 is 12769361.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16396721 - 2⁶ = 16396657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16396711) 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 7 ways as a sum of consecutive naturals, for example, 43655 + ... + 44028.

It is an arithmetic number, because the mean of its divisors is an integer number (2367468).

Almost surely, 2^16396721 is an apocalyptic number.

16396721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16396721 is a deficient number, since it is larger than the sum of its proper divisors (2543023).

16396721 is a wasteful number, since it uses less digits than its factorization.

16396721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87711.

The product of its digits is 13608, while the sum is 35.

The square root of 16396721 is about 4049.2864803568. The cubic root of 16396721 is about 254.0498848019.

The spelling of 16396721 in words is "sixteen million, three hundred ninety-six thousand, seven hundred twenty-one".