2661211728 has 120 divisors (see below), whose sum is σ = 8533231616. Its totient is φ = 758419200.

The previous prime is 2661211727. The next prime is 2661211741. The reversal of 2661211728 is 8271121662.

2661211728 is a `hidden beast` number, since 2 + 6 + 612 + 1 + 17 + 28 = 666.

It is a super-2 number, since 2×2661211728² = 14164095722489491968, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 2661211692 and 2661211701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661211727) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 421233 + ... + 427503.

Almost surely, 2^2661211728 is an apocalyptic number.

2661211728 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 2661211728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4266615808).

2661211728 is an abundant number, since it is smaller than the sum of its proper divisors (5872019888).

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

2661211728 is a wasteful number, since it uses less digits than its factorization.

2661211728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6713 (or 6704 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 2661211728 is about 51586.9336944928. The cubic root of 2661211728 is about 1385.7763424142.

The spelling of 2661211728 in words is "two billion, six hundred sixty-one million, two hundred eleven thousand, seven hundred twenty-eight".