20403400 has 72 divisors (see below), whose sum is σ = 50535270. Its totient is φ = 7659520.

The previous prime is 20403389. The next prime is 20403401. The reversal of 20403400 is 430402.

20403400 is nontrivially palindromic in base 13.

It can be written as a sum of positive squares in 9 ways, for example, as 4674244 + 15729156 = 2162^2 + 3966^2 .

It is not an unprimeable number, because it can be changed into a prime (20403401) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 57624 + ... + 57976.

Almost surely, 2^20403400 is an apocalyptic number.

20403400 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 20403400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25267635).

20403400 is an abundant number, since it is smaller than the sum of its proper divisors (30131870).

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

20403400 is a wasteful number, since it uses less digits than its factorization.

20403400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403 (or 377 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 13.

The square root of 20403400 is about 4517.0122868994. The cubic root of 20403400 is about 273.2546207352.

Adding to 20403400 its reverse (430402), we get a palindrome (20833802).

The spelling of 20403400 in words is "twenty million, four hundred three thousand, four hundred".