20728995840 has 672 divisors, whose sum is σ = 85259753280. Its totient is φ = 4558159872.

The previous prime is 20728995829. The next prime is 20728995901. The reversal of 20728995840 is 4859982702.

It is a tau number, because it is divible by the number of its divisors (672).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 74833782 + ... + 74834058.

Almost surely, 2^20728995840 is an apocalyptic number.

20728995840 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 20728995840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42629876640).

20728995840 is an abundant number, since it is smaller than the sum of its proper divisors (64530757440).

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

20728995840 is a wasteful number, since it uses less digits than its factorization.

20728995840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350 (or 323 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 54.

The spelling of 20728995840 in words is "twenty billion, seven hundred twenty-eight million, nine hundred ninety-five thousand, eight hundred forty".