20780873 has 4 divisors (see below), whose sum is σ = 20798148. Its totient is φ = 20763600.

The previous prime is 20780869. The next prime is 20780887. The reversal of 20780873 is 37808702.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5508409 + 15272464 = 2347^2 + 3908^2 .

It is a cyclic number.

It is not a de Polignac number, because 20780873 - 2² = 20780869 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20780833) 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, 6686 + ... + 9287.

It is an arithmetic number, because the mean of its divisors is an integer number (5199537).

Almost surely, 2^20780873 is an apocalyptic number.

It is an amenable number.

20780873 is a deficient number, since it is larger than the sum of its proper divisors (17275).

20780873 is a wasteful number, since it uses less digits than its factorization.

20780873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17274.

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 20780873 is about 4558.6042820144. The cubic root of 20780873 is about 274.9294496707.

The spelling of 20780873 in words is "twenty million, seven hundred eighty thousand, eight hundred seventy-three".