20805072 has 20 divisors (see below), whose sum is σ = 53746560. Its totient is φ = 6935008.

The previous prime is 20805049. The next prime is 20805089. The reversal of 20805072 is 27050802.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 216672 + ... + 216767.

It is an arithmetic number, because the mean of its divisors is an integer number (2687328).

Almost surely, 2^20805072 is an apocalyptic number.

It is an amenable number.

20805072 is an abundant number, since it is smaller than the sum of its proper divisors (32941488).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20805072 is a wasteful number, since it uses less digits than its factorization.

20805072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433450 (or 433444 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 24.

The square root of 20805072 is about 4561.2577212870. The cubic root of 20805072 is about 275.0361252818.

Adding to 20805072 its reverse (27050802), we get a palindrome (47855874).

The spelling of 20805072 in words is "twenty million, eight hundred five thousand, seventy-two".