20720355240 has 64 divisors (see below), whose sum is σ = 66942691200. Its totient is φ = 5100394752.

The previous prime is 20720355217. The next prime is 20720355241. The reversal of 20720355240 is 4255302702.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20720355198 and 20720355207.

It is not an unprimeable number, because it can be changed into a prime (20720355241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6639580 + ... + 6642699.

It is an arithmetic number, because the mean of its divisors is an integer number (1045979550).

Almost surely, 2^20720355240 is an apocalyptic number.

20720355240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20720355240 is an abundant number, since it is smaller than the sum of its proper divisors (46222335960).

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

20720355240 is a wasteful number, since it uses less digits than its factorization.

20720355240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13282306 (or 13282302 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 30.

Adding to 20720355240 its reverse (4255302702), we get a palindrome (24975657942).

The spelling of 20720355240 in words is "twenty billion, seven hundred twenty million, three hundred fifty-five thousand, two hundred forty".