20543400 has 144 divisors (see below), whose sum is σ = 70291260. Its totient is φ = 5376000.

The previous prime is 20543381. The next prime is 20543401. The reversal of 20543400 is 434502.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 6749604 + 13793796 = 2598^2 + 3714^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (20543401) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 181744 + ... + 181856.

Almost surely, 2^20543400 is an apocalyptic number.

20543400 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 20543400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35145630).

20543400 is an abundant number, since it is smaller than the sum of its proper divisors (49747860).

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

20543400 is a wasteful number, since it uses less digits than its factorization.

20543400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 18.

The square root of 20543400 is about 4532.4827633428. The cubic root of 20543400 is about 273.8781847914.

Adding to 20543400 its reverse (434502), we get a palindrome (20977902).

The spelling of 20543400 in words is "twenty million, five hundred forty-three thousand, four hundred".