2221129728 has 120 divisors (see below), whose sum is σ = 6582234960. Its totient is φ = 740229120.

The previous prime is 2221129709. The next prime is 2221129751. The reversal of 2221129728 is 8279211222.

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

It is a junction number, because it is equal to n+sod(n) for n = 2221129692 and 2221129701.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 439858 + ... + 444878.

It is an arithmetic number, because the mean of its divisors is an integer number (54851958).

Almost surely, 2^2221129728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2221129728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3291117480).

2221129728 is an abundant number, since it is smaller than the sum of its proper divisors (4361105232).

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

2221129728 is an frugal number, since it uses more digits than its factorization.

2221129728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5058 (or 5026 counting only the distinct ones).

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

The square root of 2221129728 is about 47128.8630034717. The cubic root of 2221129728 is about 1304.7419968219.

The spelling of 2221129728 in words is "two billion, two hundred twenty-one million, one hundred twenty-nine thousand, seven hundred twenty-eight".