6539790978 has 90 divisors (see below), whose sum is σ = 16572757929. Its totient is φ = 1863708336.

The previous prime is 6539790949. The next prime is 6539790989. The reversal of 6539790978 is 8790979356.

6539790978 is a `hidden beast` number, since 6 + 539 + 7 + 9 + 0 + 97 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 6047084169 + 492706809 = 77763^2 + 22197^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=57183.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 16811608 + ... + 16811996.

Almost surely, 2^6539790978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6539790978

6539790978 is an abundant number, since it is smaller than the sum of its proper divisors (10032966951).

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

6539790978 is an frugal number, since it uses more digits than its factorization.

6539790978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 814 (or 401 counting only the distinct ones).

The product of its (nonzero) digits is 25719120, while the sum is 63.

The square root of 6539790978 is about 80868.9741371807. The cubic root of 6539790978 is about 1870.0560458671.

The spelling of 6539790978 in words is "six billion, five hundred thirty-nine million, seven hundred ninety thousand, nine hundred seventy-eight".