28679891 has 4 divisors (see below), whose sum is σ = 28707984. Its totient is φ = 28651800.

The previous prime is 28679879. The next prime is 28679899. The reversal of 28679891 is 19897682.

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

It is a cyclic number.

It is not a de Polignac number, because 28679891 - 2¹⁴ = 28663507 is a prime.

It is a super-2 number, since 2×28679891² = 1645072295543762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28679899) 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, 12455 + ... + 14576.

It is an arithmetic number, because the mean of its divisors is an integer number (7176996).

Almost surely, 2^28679891 is an apocalyptic number.

28679891 is a deficient number, since it is larger than the sum of its proper divisors (28093).

28679891 is a wasteful number, since it uses less digits than its factorization.

28679891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28092.

The product of its digits is 435456, while the sum is 50.

The square root of 28679891 is about 5355.3609588897. The cubic root of 28679891 is about 306.0970650534.

The spelling of 28679891 in words is "twenty-eight million, six hundred seventy-nine thousand, eight hundred ninety-one".