16779681 has 12 divisors (see below), whose sum is σ = 24599952. Its totient is φ = 11019096.

The previous prime is 16779677. The next prime is 16779691. The reversal of 16779681 is 18697761.

It is not a de Polignac number, because 16779681 - 2² = 16779677 is a prime.

It is a super-2 number, since 2×16779681² = 563115388923522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (16779671) 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, 13311 + ... + 14516.

It is an arithmetic number, because the mean of its divisors is an integer number (2049996).

Almost surely, 2^16779681 is an apocalyptic number.

It is an amenable number.

16779681 is a deficient number, since it is larger than the sum of its proper divisors (7820271).

16779681 is a wasteful number, since it uses less digits than its factorization.

16779681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27900 (or 27897 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 16779681 is about 4096.3008922685. The cubic root of 16779681 is about 256.0125370244.

The spelling of 16779681 in words is "sixteen million, seven hundred seventy-nine thousand, six hundred eighty-one".