16440391 has 12 divisors (see below), whose sum is σ = 18299736. Its totient is φ = 14756720.

The previous prime is 16440379. The next prime is 16440397. The reversal of 16440391 is 19304461.

It is not a de Polignac number, because 16440391 - 2⁹ = 16439879 is a prime.

It is a super-3 number, since 3×16440391³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16440397) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9225 + ... + 10861.

It is an arithmetic number, because the mean of its divisors is an integer number (1524978).

Almost surely, 2^16440391 is an apocalyptic number.

16440391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

16440391 is a deficient number, since it is larger than the sum of its proper divisors (1859345).

16440391 is a wasteful number, since it uses less digits than its factorization.

16440391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1742 (or 1731 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 16440391 is about 4054.6752027752. The cubic root of 16440391 is about 254.2752250529.

The spelling of 16440391 in words is "sixteen million, four hundred forty thousand, three hundred ninety-one".