28664819 has 4 divisors (see below), whose sum is σ = 28688544. Its totient is φ = 28641096.

The previous prime is 28664809. The next prime is 28664821. The reversal of 28664819 is 91846682.

It is a happy number.

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 28664819 - 2²⁰ = 27616243 is a prime.

It is a super-2 number, since 2×28664819² = 1643343696605522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28664819.

It is not an unprimeable number, because it can be changed into a prime (28664809) 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, 9947 + ... + 12500.

It is an arithmetic number, because the mean of its divisors is an integer number (7172136).

Almost surely, 2^28664819 is an apocalyptic number.

28664819 is a deficient number, since it is larger than the sum of its proper divisors (23725).

28664819 is a wasteful number, since it uses less digits than its factorization.

28664819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23724.

The product of its digits is 165888, while the sum is 44.

The square root of 28664819 is about 5353.9535859027. The cubic root of 28664819 is about 306.0434351033.

The spelling of 28664819 in words is "twenty-eight million, six hundred sixty-four thousand, eight hundred nineteen".