28667831 has 4 divisors (see below), whose sum is σ = 30354192. Its totient is φ = 26981472.

The previous prime is 28667819. The next prime is 28667833. The reversal of 28667831 is 13876682.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28667831 is a prime.

It is a super-2 number, since 2×28667831² = 1643689068489122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28667833) 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, 843155 + ... + 843188.

It is an arithmetic number, because the mean of its divisors is an integer number (7588548).

Almost surely, 2^28667831 is an apocalyptic number.

28667831 is a deficient number, since it is larger than the sum of its proper divisors (1686361).

28667831 is a wasteful number, since it uses less digits than its factorization.

28667831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1686360.

The product of its digits is 96768, while the sum is 41.

The square root of 28667831 is about 5354.2348659729. The cubic root of 28667831 is about 306.0541540563.

The spelling of 28667831 in words is "twenty-eight million, six hundred sixty-seven thousand, eight hundred thirty-one".