20728571240 has 96 divisors (see below), whose sum is σ = 53355629880. Its totient is φ = 7203360768.

The previous prime is 20728571239. The next prime is 20728571249. The reversal of 20728571240 is 4217582702.

It can be written as a sum of positive squares in 12 ways, for example, as 6400960036 + 14327611204 = 80006^2 + 119698^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20728571194 and 20728571203.

It is not an unprimeable number, because it can be changed into a prime (20728571249) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 81314 + ... + 219246.

Almost surely, 2^20728571240 is an apocalyptic number.

20728571240 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 20728571240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26677814940).

20728571240 is an abundant number, since it is smaller than the sum of its proper divisors (32627058640).

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

20728571240 is a wasteful number, since it uses less digits than its factorization.

20728571240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137991 (or 137970 counting only the distinct ones).

The product of its (nonzero) digits is 62720, while the sum is 38.

The spelling of 20728571240 in words is "twenty billion, seven hundred twenty-eight million, five hundred seventy-one thousand, two hundred forty".