16778881 has 32 divisors (see below), whose sum is σ = 22014720. Its totient is φ = 12441600.

The previous prime is 16778869. The next prime is 16778887. The reversal of 16778881 is 18887761.

It is a 2-Lehmer number, since φ(16778881) divides (16778881-1)².

It is a cyclic number.

It is a Carmichael number.

It is not a de Polignac number, because 16778881 - 2¹¹ = 16776833 is a prime.

It is a super-2 number, since 2×16778881² = 563061695224322, which contains 22 as substring.

It is a deceptive number, since it divides R_16778880.

It is not an unprimeable number, because it can be changed into a prime (16778887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 92611 + ... + 92791.

It is an arithmetic number, because the mean of its divisors is an integer number (687960).

It is a Poulet number, since it divides 2^16778880-1.

Almost surely, 2^16778881 is an apocalyptic number.

It is an amenable number.

16778881 is a deficient number, since it is larger than the sum of its proper divisors (5235839).

16778881 is a wasteful number, since it uses less digits than its factorization.

16778881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265.

The product of its digits is 150528, while the sum is 46.

The square root of 16778881 is about 4096.2032420279. The cubic root of 16778881 is about 256.0084683478.

The spelling of 16778881 in words is "sixteen million, seven hundred seventy-eight thousand, eight hundred eighty-one".