20400500 has 24 divisors (see below), whose sum is σ = 44555784. Its totient is φ = 8160000.

The previous prime is 20400481. The next prime is 20400521. The reversal of 20400500 is 500402.

It can be written as a sum of positive squares in 4 ways, for example, as 132496 + 20268004 = 364^2 + 4502^2 .

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 19901 + ... + 20900.

It is an arithmetic number, because the mean of its divisors is an integer number (1856491).

Almost surely, 2^20400500 is an apocalyptic number.

20400500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20400500 is an abundant number, since it is smaller than the sum of its proper divisors (24155284).

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

20400500 is a wasteful number, since it uses less digits than its factorization.

20400500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40820 (or 40808 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 11.

The square root of 20400500 is about 4516.6912668457. The cubic root of 20400500 is about 273.2416739396.

Adding to 20400500 its reverse (500402), we get a palindrome (20900902).

The spelling of 20400500 in words is "twenty million, four hundred thousand, five hundred".