20409644728 has 64 divisors (see below), whose sum is σ = 42208358400. Its totient is φ = 9175057920.

The previous prime is 20409644659. The next prime is 20409644753. The reversal of 20409644728 is 82744690402.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

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, 3763603 + ... + 3769021.

It is an arithmetic number, because the mean of its divisors is an integer number (659505600).

Almost surely, 2^20409644728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20409644728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21104179200).

20409644728 is an abundant number, since it is smaller than the sum of its proper divisors (21798713672).

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

20409644728 is a wasteful number, since it uses less digits than its factorization.

20409644728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5900 (or 5896 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 46.

The spelling of 20409644728 in words is "twenty billion, four hundred nine million, six hundred forty-four thousand, seven hundred twenty-eight".