16778481 has 4 divisors (see below), whose sum is σ = 22371312. Its totient is φ = 11185652.

The previous prime is 16778453. The next prime is 16778497. The reversal of 16778481 is 18487761.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16778481 - 2⁵ = 16778449 is a prime.

It is a super-2 number, since 2×16778481² = 563034849334722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (16778401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2796411 + ... + 2796416.

It is an arithmetic number, because the mean of its divisors is an integer number (5592828).

Almost surely, 2^16778481 is an apocalyptic number.

It is an amenable number.

16778481 is a deficient number, since it is larger than the sum of its proper divisors (5592831).

16778481 is an equidigital number, since it uses as much as digits as its factorization.

16778481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5592830.

The product of its digits is 75264, while the sum is 42.

The square root of 16778481 is about 4096.1544160346. The cubic root of 16778481 is about 256.0064339610.

The spelling of 16778481 in words is "sixteen million, seven hundred seventy-eight thousand, four hundred eighty-one".