20400543 has 12 divisors (see below), whose sum is σ = 30483960. Its totient is φ = 13131216.

The previous prime is 20400539. The next prime is 20400577. The reversal of 20400543 is 34500402.

It is a happy number.

It is not a de Polignac number, because 20400543 - 2² = 20400539 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20408543) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38821 + ... + 39342.

It is an arithmetic number, because the mean of its divisors is an integer number (2540330).

Almost surely, 2^20400543 is an apocalyptic number.

20400543 is a deficient number, since it is larger than the sum of its proper divisors (10083417).

20400543 is a wasteful number, since it uses less digits than its factorization.

20400543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78198 (or 78195 counting only the distinct ones).

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

The square root of 20400543 is about 4516.6960269648. The cubic root of 20400543 is about 273.2418659183.

Adding to 20400543 its reverse (34500402), we get a palindrome (54900945).

The spelling of 20400543 in words is "twenty million, four hundred thousand, five hundred forty-three".