20500400 has 60 divisors (see below), whose sum is σ = 50233392. Its totient is φ = 8037120.

The previous prime is 20500397. The next prime is 20500423. The reversal of 20500400 is 400502.

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 11 ways as a sum of consecutive naturals, for example, 20717 + ... + 21683.

Almost surely, 2^20500400 is an apocalyptic number.

20500400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20500400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25116696).

20500400 is an abundant number, since it is smaller than the sum of its proper divisors (29732992).

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

20500400 is a wasteful number, since it uses less digits than its factorization.

20500400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1038 (or 1027 counting only the distinct ones).

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

The square root of 20500400 is about 4527.7367414637. The cubic root of 20500400 is about 273.6869637946.

Adding to 20500400 its reverse (400502), we get a palindrome (20900902).

The spelling of 20500400 in words is "twenty million, five hundred thousand, four hundred".