28879391 has 4 divisors (see below), whose sum is σ = 29030784. Its totient is φ = 28728000.

The previous prime is 28879387. The next prime is 28879393. The reversal of 28879391 is 19397882.

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 28879391 - 2² = 28879387 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28879393) 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, 75410 + ... + 75791.

It is an arithmetic number, because the mean of its divisors is an integer number (7257696).

Almost surely, 2^28879391 is an apocalyptic number.

28879391 is a deficient number, since it is larger than the sum of its proper divisors (151393).

28879391 is a wasteful number, since it uses less digits than its factorization.

28879391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151392.

The product of its digits is 217728, while the sum is 47.

The square root of 28879391 is about 5373.9548751362. The cubic root of 28879391 is about 306.8051722856.

The spelling of 28879391 in words is "twenty-eight million, eight hundred seventy-nine thousand, three hundred ninety-one".