6505391880 has 336 divisors, whose sum is σ = 23815573740. Its totient is φ = 1589103360.

The previous prime is 6505391839. The next prime is 6505391929. The reversal of 6505391880 is 881935056.

It can be written as a sum of positive squares in 2 ways, for example, as 6055018596 + 450373284 = 77814^2 + 21222^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 49659415 + ... + 49659545.

Almost surely, 2^6505391880 is an apocalyptic number.

6505391880 is a gapful number since it is divisible by the number (60) 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 6505391880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11907786870).

6505391880 is an abundant number, since it is smaller than the sum of its proper divisors (17310181860).

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

6505391880 is a wasteful number, since it uses less digits than its factorization.

6505391880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The square root of 6505391880 is about 80656.0095715130. The cubic root of 6505391880 is about 1866.7714678972.

The spelling of 6505391880 in words is "six billion, five hundred five million, three hundred ninety-one thousand, eight hundred eighty".