16303721 has 6 divisors (see below), whose sum is σ = 18965610. Its totient is φ = 13974576.

The previous prime is 16303699. The next prime is 16303733. The reversal of 16303721 is 12730361.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 9486400 + 6817321 = 3080^2 + 2611^2 .

It is not a de Polignac number, because 16303721 - 2⁶ = 16303657 is a prime.

It is a super-2 number, since 2×16303721² = 531622636891682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16303741) 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 5 ways as a sum of consecutive naturals, for example, 166316 + ... + 166413.

It is an arithmetic number, because the mean of its divisors is an integer number (3160935).

Almost surely, 2^16303721 is an apocalyptic number.

It is an amenable number.

16303721 is a deficient number, since it is larger than the sum of its proper divisors (2661889).

16303721 is an equidigital number, since it uses as much as digits as its factorization.

16303721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332743 (or 332736 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 23.

The square root of 16303721 is about 4037.7866461714. The cubic root of 16303721 is about 253.5686615619.

The spelling of 16303721 in words is "sixteen million, three hundred three thousand, seven hundred twenty-one".