2661457656 has 128 divisors (see below), whose sum is σ = 8028518400. Its totient is φ = 724308480.

The previous prime is 2661457651. The next prime is 2661457679. The reversal of 2661457656 is 6567541662.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661457651) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 116505 + ... + 137463.

It is an arithmetic number, because the mean of its divisors is an integer number (62722800).

Almost surely, 2^2661457656 is an apocalyptic number.

2661457656 is a gapful number since it is divisible by the number (26) 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 2661457656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4014259200).

2661457656 is an abundant number, since it is smaller than the sum of its proper divisors (5367060744).

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

2661457656 is a wasteful number, since it uses less digits than its factorization.

2661457656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21029 (or 21025 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 48.

The square root of 2661457656 is about 51589.3172662713. The cubic root of 2661457656 is about 1385.8190285714.

The spelling of 2661457656 in words is "two billion, six hundred sixty-one million, four hundred fifty-seven thousand, six hundred fifty-six".