6446820864 has 80 divisors (see below), whose sum is σ = 18736122240. Its totient is φ = 1953576960.

The previous prime is 6446820839. The next prime is 6446820871. The reversal of 6446820864 is 4680286446.

It is a super-2 number, since 2×6446820864² = 83122998505011412992, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 173884 + ... + 207675.

It is an arithmetic number, because the mean of its divisors is an integer number (234201528).

Almost surely, 2^6446820864 is an apocalyptic number.

6446820864 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

6446820864 is an abundant number, since it is smaller than the sum of its proper divisors (12289301376).

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

6446820864 is a wasteful number, since it uses less digits than its factorization.

6446820864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381591 (or 381575 counting only the distinct ones).

The product of its (nonzero) digits is 1769472, while the sum is 48.

The square root of 6446820864 is about 80292.0971453605. The cubic root of 6446820864 is about 1861.1521038940.

The spelling of 6446820864 in words is "six billion, four hundred forty-six million, eight hundred twenty thousand, eight hundred sixty-four".