820020240 has 640 divisors, whose sum is σ = 3374784000. Its totient is φ = 181149696.

The previous prime is 820020239. The next prime is 820020241. The reversal of 820020240 is 42020028.

It is an interprime number because it is at equal distance from previous prime (820020239) and next prime (820020241).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (820020241) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 15472054 + ... + 15472106.

It is an arithmetic number, because the mean of its divisors is an integer number (5273100).

Almost surely, 2^820020240 is an apocalyptic number.

820020240 is a gapful number since it is divisible by the number (80) 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 820020240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1687392000).

820020240 is an abundant number, since it is smaller than the sum of its proper divisors (2554763760).

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

820020240 is a wasteful number, since it uses less digits than its factorization.

820020240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136 (or 124 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 820020240 is about 28635.9955301016. The cubic root of 820020240 is about 935.9978632430.

Adding to 820020240 its product of nonzero digits (256), we get a square (820020496 = 28636²).

Adding to 820020240 its reverse (42020028), we get a palindrome (862040268).

The spelling of 820020240 in words is "eight hundred twenty million, twenty thousand, two hundred forty".