28067681 has 4 divisors (see below), whose sum is σ = 28094100. Its totient is φ = 28041264.

The previous prime is 28067653. The next prime is 28067701. The reversal of 28067681 is 18676082.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6677056 + 21390625 = 2584^2 + 4625^2 .

It is a cyclic number.

It is not a de Polignac number, because 28067681 - 2¹⁴ = 28051297 is a prime.

It is a super-2 number, since 2×28067681² = 1575589433435522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28067651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11546 + ... + 13763.

It is an arithmetic number, because the mean of its divisors is an integer number (7023525).

Almost surely, 2^28067681 is an apocalyptic number.

It is an amenable number.

28067681 is a deficient number, since it is larger than the sum of its proper divisors (26419).

28067681 is a wasteful number, since it uses less digits than its factorization.

28067681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26418.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 28067681 is about 5297.8940155500. The cubic root of 28067681 is about 303.9033662446.

The spelling of 28067681 in words is "twenty-eight million, sixty-seven thousand, six hundred eighty-one".