6461819920 has 20 divisors (see below), whose sum is σ = 15023731500. Its totient is φ = 2584727936.

The previous prime is 6461819899. The next prime is 6461819963. The reversal of 6461819920 is 299181646.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 3332983824 + 3128836096 = 57732^2 + 55936^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40386295 + ... + 40386454.

It is an arithmetic number, because the mean of its divisors is an integer number (751186575).

Almost surely, 2^6461819920 is an apocalyptic number.

It is an amenable number.

6461819920 is an abundant number, since it is smaller than the sum of its proper divisors (8561911580).

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

6461819920 is a wasteful number, since it uses less digits than its factorization.

6461819920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80772762 (or 80772756 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 46.

The square root of 6461819920 is about 80385.4459463901. The cubic root of 6461819920 is about 1862.5943601579.

The spelling of 6461819920 in words is "six billion, four hundred sixty-one million, eight hundred nineteen thousand, nine hundred twenty".