6515091780 has 192 divisors, whose sum is σ = 19524976128. Its totient is φ = 1619537920.

The previous prime is 6515091769. The next prime is 6515091787. The reversal of 6515091780 is 871905156.

It is not an unprimeable number, because it can be changed into a prime (6515091787) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 20552182 + ... + 20552498.

It is an arithmetic number, because the mean of its divisors is an integer number (101692584).

Almost surely, 2^6515091780 is an apocalyptic number.

6515091780 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 6515091780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9762488064).

6515091780 is an abundant number, since it is smaller than the sum of its proper divisors (13009884348).

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

6515091780 is a wasteful number, since it uses less digits than its factorization.

6515091780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 686 (or 684 counting only the distinct ones).

The product of its (nonzero) digits is 75600, while the sum is 42.

The square root of 6515091780 is about 80716.1184646536. The cubic root of 6515091780 is about 1867.6988270572.

The spelling of 6515091780 in words is "six billion, five hundred fifteen million, ninety-one thousand, seven hundred eighty".