20400505040 has 80 divisors (see below), whose sum is σ = 49538936448. Its totient is φ = 7798230528.

The previous prime is 20400505033. The next prime is 20400505091. The reversal of 20400505040 is 4050500402.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

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

It is a congruent number.

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, 2271599 + ... + 2280561.

Almost surely, 2^20400505040 is an apocalyptic number.

20400505040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20400505040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24769468224).

20400505040 is an abundant number, since it is smaller than the sum of its proper divisors (29138431408).

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

20400505040 is a wasteful number, since it uses less digits than its factorization.

20400505040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10236 (or 10230 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 20.

The spelling of 20400505040 in words is "twenty billion, four hundred million, five hundred five thousand, forty".