16988721 has 8 divisors (see below), whose sum is σ = 22989984. Its totient is φ = 11156640.

The previous prime is 16988707. The next prime is 16988749. The reversal of 16988721 is 12788961.

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

It is not a de Polignac number, because 16988721 - 2¹⁷ = 16857649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16988791) 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, 42060 + ... + 42461.

It is an arithmetic number, because the mean of its divisors is an integer number (2873748).

Almost surely, 2^16988721 is an apocalyptic number.

It is an amenable number.

16988721 is a deficient number, since it is larger than the sum of its proper divisors (6001263).

16988721 is an equidigital number, since it uses as much as digits as its factorization.

16988721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84591.

The product of its digits is 48384, while the sum is 42.

The square root of 16988721 is about 4121.7376190146. The cubic root of 16988721 is about 257.0712808280.

The spelling of 16988721 in words is "sixteen million, nine hundred eighty-eight thousand, seven hundred twenty-one".