28039979 has 4 divisors (see below), whose sum is σ = 30589080. Its totient is φ = 25490880.

The previous prime is 28039961. The next prime is 28039981. The reversal of 28039979 is 97993082.

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 28039979 - 2²⁰ = 26991403 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28039909) 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, 1274534 + ... + 1274555.

It is an arithmetic number, because the mean of its divisors is an integer number (7647270).

Almost surely, 2^28039979 is an apocalyptic number.

28039979 is a deficient number, since it is larger than the sum of its proper divisors (2549101).

28039979 is a wasteful number, since it uses less digits than its factorization.

28039979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2549100.

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 28039979 is about 5295.2789350515. The cubic root of 28039979 is about 303.8033520176.

The spelling of 28039979 in words is "twenty-eight million, thirty-nine thousand, nine hundred seventy-nine".