6447820 has 48 divisors (see below), whose sum is σ = 14370048. Its totient is φ = 2425280.

The previous prime is 6447817. The next prime is 6447829. The reversal of 6447820 is 287446.

It is not an unprimeable number, because it can be changed into a prime (6447829) 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, 49155 + ... + 49285.

It is an arithmetic number, because the mean of its divisors is an integer number (299376).

Almost surely, 2^6447820 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 6447820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7185024).

6447820 is an abundant number, since it is smaller than the sum of its proper divisors (7922228).

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

6447820 is a wasteful number, since it uses less digits than its factorization.

6447820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 31.

The square root of 6447820 is about 2539.2557964884. The cubic root of 6447820 is about 186.1248246786.

It can be divided in two parts, 644 and 7820, that added together give a square (8464 = 92²).

The spelling of 6447820 in words is "six million, four hundred forty-seven thousand, eight hundred twenty".