20208400128 has 576 divisors, whose sum is σ = 71535421440. Its totient is φ = 5507481600.

The previous prime is 20208400111. The next prime is 20208400141. The reversal of 20208400128 is 82100480202.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 121008301 + ... + 121008467.

It is an arithmetic number, because the mean of its divisors is an integer number (124193440).

Almost surely, 2^20208400128 is an apocalyptic number.

20208400128 is a gapful number since it is divisible by the number (28) 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 20208400128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35767710720).

20208400128 is an abundant number, since it is smaller than the sum of its proper divisors (51327021312).

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

20208400128 is a wasteful number, since it uses less digits than its factorization.

20208400128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301 (or 281 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The spelling of 20208400128 in words is "twenty billion, two hundred eight million, four hundred thousand, one hundred twenty-eight".