788435667721 has 27 divisors (see below), whose sum is σ = 860997868821. Its totient is φ = 721659991104.

The previous prime is 788435667689. The next prime is 788435667749. The reversal of 788435667721 is 127766534887.

The square root of 788435667721 is 887939.

It is a perfect power (a square), and thus also a powerful number.

788435667721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 7396860025 + 781038807696 = 86005^2 + 883764^2 .

It is not a de Polignac number, because 788435667721 - 2⁵ = 788435667689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (788435667791) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1927715365 + ... + 1927715773.

Almost surely, 2^788435667721 is an apocalyptic number.

788435667721 is the 887939-th square number.

788435667721 is the 443970-th centered octagonal number.

It is an amenable number.

788435667721 is a deficient number, since it is larger than the sum of its proper divisors (72562201100).

788435667721 is an frugal number, since it uses more digits than its factorization.

788435667721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1178 (or 589 counting only the distinct ones).

The product of its digits is 94832640, while the sum is 64.

Multiplying 788435667721 by its sum of digits (64), we get a square (50459882734144 = 7103512²).

The spelling of 788435667721 in words is "seven hundred eighty-eight billion, four hundred thirty-five million, six hundred sixty-seven thousand, seven hundred twenty-one".