20728806 has 32 divisors (see below), whose sum is σ = 48664320. Its totient is φ = 5762016.

The previous prime is 20728787. The next prime is 20728811. The reversal of 20728806 is 60882702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5116 + ... + 8223.

It is an arithmetic number, because the mean of its divisors is an integer number (1520760).

Almost surely, 2^20728806 is an apocalyptic number.

20728806 is an abundant number, since it is smaller than the sum of its proper divisors (27935514).

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

20728806 is a wasteful number, since it uses less digits than its factorization.

20728806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13388.

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 20728806 is about 4552.8898515119. The cubic root of 20728806 is about 274.6996434181.

It can be divided in two parts, 2072 and 8806, that added together give a triangular number (10878 = T₁₄₇).

The spelling of 20728806 in words is "twenty million, seven hundred twenty-eight thousand, eight hundred six".