20400821424 has 120 divisors (see below), whose sum is σ = 59513266800. Its totient is φ = 6517615104.

The previous prime is 20400821383. The next prime is 20400821443. The reversal of 20400821424 is 42412800402.

20400821424 is a `hidden beast` number, since 20 + 400 + 8 + 214 + 24 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 328402 + ... + 385550.

It is an arithmetic number, because the mean of its divisors is an integer number (495943890).

Almost surely, 2^20400821424 is an apocalyptic number.

20400821424 is a gapful number since it is divisible by the number (24) 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 20400821424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29756633400).

20400821424 is an abundant number, since it is smaller than the sum of its proper divisors (39112445376).

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

20400821424 is a wasteful number, since it uses less digits than its factorization.

20400821424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57267 (or 57258 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 27.

The spelling of 20400821424 in words is "twenty billion, four hundred million, eight hundred twenty-one thousand, four hundred twenty-four".