20505812 has 12 divisors (see below), whose sum is σ = 35919156. Its totient is φ = 10243200.

The previous prime is 20505809. The next prime is 20505829. The reversal of 20505812 is 21850502.

It can be written as a sum of positive squares in 2 ways, for example, as 3083536 + 17422276 = 1756^2 + 4174^2 .

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

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, 4562 + ... + 7862.

It is an arithmetic number, because the mean of its divisors is an integer number (2993263).

Almost surely, 2^20505812 is an apocalyptic number.

It is an amenable number.

20505812 is a deficient number, since it is larger than the sum of its proper divisors (15413344).

20505812 is a wasteful number, since it uses less digits than its factorization.

20505812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4858 (or 4856 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 20505812 is about 4528.3343516132. The cubic root of 20505812 is about 273.7110456584.

The spelling of 20505812 in words is "twenty million, five hundred five thousand, eight hundred twelve".