2661256516128 has 144 divisors (see below), whose sum is σ = 8140428936864. Its totient is φ = 759040450560.

The previous prime is 2661256516111. The next prime is 2661256516129. The reversal of 2661256516128 is 8216156521662.

It is a super-2 number, since 2×2661256516128² (a number of 26 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2661256516129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2223963 + ... + 3204453.

It is an arithmetic number, because the mean of its divisors is an integer number (56530756506).

Almost surely, 2^{2661256516128} is an apocalyptic number.

2661256516128 is a gapful number since it is divisible by the number (28) 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 2661256516128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4070214468432).

2661256516128 is an abundant number, since it is smaller than the sum of its proper divisors (5479172420736).

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

2661256516128 is a wasteful number, since it uses less digits than its factorization.

2661256516128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 981095 (or 981080 counting only the distinct ones).

The product of its digits is 2073600, while the sum is 51.

The spelling of 2661256516128 in words is "two trillion, six hundred sixty-one billion, two hundred fifty-six million, five hundred sixteen thousand, one hundred twenty-eight".