16040721 has 8 divisors (see below), whose sum is σ = 21965824. Its totient is φ = 10404720.

The previous prime is 16040699. The next prime is 16040747. The reversal of 16040721 is 12704061.

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

It is not a de Polignac number, because 16040721 - 2⁹ = 16040209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16040221) 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 7 ways as a sum of consecutive naturals, for example, 72145 + ... + 72366.

It is an arithmetic number, because the mean of its divisors is an integer number (2745728).

Almost surely, 2^16040721 is an apocalyptic number.

It is an amenable number.

16040721 is a deficient number, since it is larger than the sum of its proper divisors (5925103).

16040721 is a wasteful number, since it uses less digits than its factorization.

16040721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144551.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 16040721 is about 4005.0868904432. The cubic root of 16040721 is about 252.1978007352.

Adding to 16040721 its reverse (12704061), we get a palindrome (28744782).

It can be divided in two parts, 16040 and 721, that added together give a palindrome (16761).

The spelling of 16040721 in words is "sixteen million, forty thousand, seven hundred twenty-one".