20400404240 has 20 divisors (see below), whose sum is σ = 47430940044. Its totient is φ = 8160161664.

The previous prime is 20400404237. The next prime is 20400404279. The reversal of 20400404240 is 4240400402.

It can be written as a sum of positive squares in 2 ways, for example, as 8276632576 + 12123771664 = 90976^2 + 110108^2 .

It is a tau number, because it is divible by the number of its divisors (20).

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127502447 + ... + 127502606.

Almost surely, 2^20400404240 is an apocalyptic number.

20400404240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20400404240 is an abundant number, since it is smaller than the sum of its proper divisors (27030535804).

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

20400404240 is a wasteful number, since it uses less digits than its factorization.

20400404240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255005066 (or 255005060 counting only the distinct ones).

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

Adding to 20400404240 its reverse (4240400402), we get a palindrome (24640804642).

The spelling of 20400404240 in words is "twenty billion, four hundred million, four hundred four thousand, two hundred forty".