6591661956 has 192 divisors, whose sum is σ = 19111680000. Its totient is φ = 1947853440.

The previous prime is 6591661943. The next prime is 6591661987.

6591661956 is a `hidden beast` number, since 6 + 5 + 9 + 16 + 619 + 5 + 6 = 666.

6591661956 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11004145 + ... + 11004743.

It is an arithmetic number, because the mean of its divisors is an integer number (99540000).

Almost surely, 2^6591661956 is an apocalyptic number.

6591661956 is a gapful number since it is divisible by the number (66) 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 6591661956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9555840000).

6591661956 is an abundant number, since it is smaller than the sum of its proper divisors (12520018044).

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

6591661956 is a wasteful number, since it uses less digits than its factorization.

6591661956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 839 (or 831 counting only the distinct ones).

The product of its digits is 2624400, while the sum is 54.

The square root of 6591661956 is about 81189.0507149825. The cubic root of 6591661956 is about 1874.9872075927.

The spelling of 6591661956 in words is "six billion, five hundred ninety-one million, six hundred sixty-one thousand, nine hundred fifty-six".