2661997128 has 192 divisors, whose sum is σ = 8231256000. Its totient is φ = 713276928.

The previous prime is 2661997127. The next prime is 2661997157. The reversal of 2661997128 is 8217991662.

2661997128 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (2661997127) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2434950 + ... + 2436042.

It is an arithmetic number, because the mean of its divisors is an integer number (42871125).

Almost surely, 2^2661997128 is an apocalyptic number.

2661997128 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 2661997128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4115628000).

2661997128 is an abundant number, since it is smaller than the sum of its proper divisors (5569258872).

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

2661997128 is a wasteful number, since it uses less digits than its factorization.

2661997128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1244 (or 1233 counting only the distinct ones).

The product of its digits is 653184, while the sum is 51.

The square root of 2661997128 is about 51594.5455256658. The cubic root of 2661997128 is about 1385.9126564691.

The spelling of 2661997128 in words is "two billion, six hundred sixty-one million, nine hundred ninety-seven thousand, one hundred twenty-eight".