2123656728 has 64 divisors (see below), whose sum is σ = 5662625760. Its totient is φ = 661364736.

The previous prime is 2123656709. The next prime is 2123656739. The reversal of 2123656728 is 8276563212.

It is a self number, because there is not a number n which added to its sum of digits gives 2123656728.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36900 + ... + 74892.

Almost surely, 2^2123656728 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 2123656728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2831312880).

2123656728 is an abundant number, since it is smaller than the sum of its proper divisors (3538969032).

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

2123656728 is a wasteful number, since it uses less digits than its factorization.

2123656728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38156 (or 38152 counting only the distinct ones).

The product of its digits is 241920, while the sum is 42.

The square root of 2123656728 is about 46083.1501527402. The cubic root of 2123656728 is about 1285.3698417137.

The spelling of 2123656728 in words is "two billion, one hundred twenty-three million, six hundred fifty-six thousand, seven hundred twenty-eight".