20400304505 has 24 divisors (see below), whose sum is σ = 28488921480. Its totient is φ = 13983002880.

The previous prime is 20400304501. The next prime is 20400304511. The reversal of 20400304505 is 50540300402.

It can be written as a sum of positive squares in 4 ways, for example, as 2726197369 + 17674107136 = 52213^2 + 132944^2 .

It is not a de Polignac number, because 20400304505 - 2² = 20400304501 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20400304501) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 626261 + ... + 658029.

It is an arithmetic number, because the mean of its divisors is an integer number (1187038395).

Almost surely, 2^20400304505 is an apocalyptic number.

It is an amenable number.

20400304505 is a deficient number, since it is larger than the sum of its proper divisors (8088616975).

20400304505 is a wasteful number, since it uses less digits than its factorization.

20400304505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34409 (or 34402 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 23.

Adding to 20400304505 its reverse (50540300402), we get a palindrome (70940604907).

The spelling of 20400304505 in words is "twenty billion, four hundred million, three hundred four thousand, five hundred five".