20865079 has 4 divisors (see below), whose sum is σ = 21150976. Its totient is φ = 20579184.

The previous prime is 20865067. The next prime is 20865083. The reversal of 20865079 is 97056802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97056802 = 2 ⋅48528401.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20865079 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 (20865179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142839 + ... + 142984.

It is an arithmetic number, because the mean of its divisors is an integer number (5287744).

Almost surely, 2^20865079 is an apocalyptic number.

20865079 is a deficient number, since it is larger than the sum of its proper divisors (285897).

20865079 is an equidigital number, since it uses as much as digits as its factorization.

20865079 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285896.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 20865079 is about 4567.8308856612. The cubic root of 20865079 is about 275.3002956540.

The spelling of 20865079 in words is "twenty million, eight hundred sixty-five thousand, seventy-nine".