20400436 has 24 divisors (see below), whose sum is σ = 40896576. Its totient is φ = 8722560.

The previous prime is 20400421. The next prime is 20400437. The reversal of 20400436 is 63400402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20400437) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22716 + ... + 23596.

It is an arithmetic number, because the mean of its divisors is an integer number (1704024).

Almost surely, 2^20400436 is an apocalyptic number.

It is an amenable number.

20400436 is an abundant number, since it is smaller than the sum of its proper divisors (20496140).

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

20400436 is a wasteful number, since it uses less digits than its factorization.

20400436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1719 (or 1717 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 20400436 is about 4516.6841820079. The cubic root of 20400436 is about 273.2413882034.

Adding to 20400436 its reverse (63400402), we get a palindrome (83800838).

The spelling of 20400436 in words is "twenty million, four hundred thousand, four hundred thirty-six".