20406500 has 24 divisors (see below), whose sum is σ = 44568888. Its totient is φ = 8162400.

The previous prime is 20406461. The next prime is 20406521. The reversal of 20406500 is 560402.

It can be written as a sum of positive squares in 4 ways, for example, as 550564 + 19855936 = 742^2 + 4456^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19907 + ... + 20906.

It is an arithmetic number, because the mean of its divisors is an integer number (1857037).

Almost surely, 2^20406500 is an apocalyptic number.

20406500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20406500 is an abundant number, since it is smaller than the sum of its proper divisors (24162388).

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

20406500 is a wasteful number, since it uses less digits than its factorization.

20406500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40832 (or 40820 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 20406500 is about 4517.3554210401. The cubic root of 20406500 is about 273.2684590567.

Adding to 20406500 its reverse (560402), we get a palindrome (20966902).

The spelling of 20406500 in words is "twenty million, four hundred six thousand, five hundred".