20420404040 has 32 divisors (see below), whose sum is σ = 45973786680. Its totient is φ = 8163205632.

The previous prime is 20420404021. The next prime is 20420404049. The reversal of 20420404040 is 4040402402.

It can be written as a sum of positive squares in 4 ways, for example, as 15088191556 + 5332212484 = 122834^2 + 73022^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (20420404049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87767 + ... + 220326.

Almost surely, 2^20420404040 is an apocalyptic number.

20420404040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20420404040 is an abundant number, since it is smaller than the sum of its proper divisors (25553382640).

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

20420404040 is a wasteful number, since it uses less digits than its factorization.

20420404040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309761 (or 309757 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 20.

Adding to 20420404040 its reverse (4040402402), we get a palindrome (24460806442).

The spelling of 20420404040 in words is "twenty billion, four hundred twenty million, four hundred four thousand, forty".