16549381 has 12 divisors (see below), whose sum is σ = 18124236. Its totient is φ = 15058560.

The previous prime is 16549349. The next prime is 16549387. The reversal of 16549381 is 18394561.

It can be written as a sum of positive squares in 2 ways, for example, as 4708900 + 11840481 = 2170^2 + 3441^2 .

It is not a de Polignac number, because 16549381 - 2⁵ = 16549349 is a prime.

It is a super-2 number, since 2×16549381² = 547764022966322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16549381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16549387) 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 11 ways as a sum of consecutive naturals, for example, 15831 + ... + 16843.

It is an arithmetic number, because the mean of its divisors is an integer number (1510353).

Almost surely, 2^16549381 is an apocalyptic number.

It is an amenable number.

16549381 is a deficient number, since it is larger than the sum of its proper divisors (1574855).

16549381 is a wasteful number, since it uses less digits than its factorization.

16549381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1092 (or 1061 counting only the distinct ones).

The product of its digits is 25920, while the sum is 37.

The square root of 16549381 is about 4068.0930422005. The cubic root of 16549381 is about 254.8358856865.

The spelling of 16549381 in words is "sixteen million, five hundred forty-nine thousand, three hundred eighty-one".