20408905440 has 864 divisors, whose sum is σ = 90662120640. Its totient is φ = 4087480320.

The previous prime is 20408905427. The next prime is 20408905529. The reversal of 20408905440 is 4450980402.

20408905440 is a `hidden beast` number, since 20 + 4 + 0 + 8 + 90 + 544 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20408905395 and 20408905404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 35370432 + ... + 35371008.

It is an arithmetic number, because the mean of its divisors is an integer number (104933010).

Almost surely, 2^20408905440 is an apocalyptic number.

20408905440 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 20408905440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45331060320).

20408905440 is an abundant number, since it is smaller than the sum of its proper divisors (70253215200).

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

20408905440 is a wasteful number, since it uses less digits than its factorization.

20408905440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656 (or 634 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The spelling of 20408905440 in words is "twenty billion, four hundred eight million, nine hundred five thousand, four hundred forty".