20400020040 has 64 divisors (see below), whose sum is σ = 61211505600. Its totient is φ = 5438988032.

The previous prime is 20400020029. The next prime is 20400020057. The reversal of 20400020040 is 4002000402.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a junction number, because it is equal to n+sod(n) for n = 20400019998 and 20400020025.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 803866 + ... + 828854.

It is an arithmetic number, because the mean of its divisors is an integer number (956429775).

Almost surely, 2^20400020040 is an apocalyptic number.

20400020040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20400020040 is an abundant number, since it is smaller than the sum of its proper divisors (40811485560).

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

20400020040 is a wasteful number, since it uses less digits than its factorization.

20400020040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31806 (or 31802 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 12.

Adding to 20400020040 its reverse (4002000402), we get a palindrome (24402020442).

The spelling of 20400020040 in words is "twenty billion, four hundred million, twenty thousand, forty".