16913721 has 8 divisors (see below), whose sum is σ = 24601824. Its totient is φ = 10250720.

The previous prime is 16913719. The next prime is 16913737. The reversal of 16913721 is 12731961.

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 16913721 - 2¹ = 16913719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16913761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 256236 + ... + 256301.

It is an arithmetic number, because the mean of its divisors is an integer number (3075228).

Almost surely, 2^16913721 is an apocalyptic number.

16913721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16913721 is a deficient number, since it is larger than the sum of its proper divisors (7688103).

16913721 is a wasteful number, since it uses less digits than its factorization.

16913721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512551.

The product of its digits is 2268, while the sum is 30.

The square root of 16913721 is about 4112.6294508501. The cubic root of 16913721 is about 256.6924257800.

The spelling of 16913721 in words is "sixteen million, nine hundred thirteen thousand, seven hundred twenty-one".