638780523261 has 16 divisors (see below), whose sum is σ = 897887797248. Its totient is φ = 403348028400.

The previous prime is 638780523247. The next prime is 638780523299. The reversal of 638780523261 is 162325087836.

It is a happy number.

638780523261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 638780523261 - 2¹¹ = 638780521213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638780523061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73065925 + ... + 73074666.

It is an arithmetic number, because the mean of its divisors is an integer number (56117987328).

Almost surely, 2^638780523261 is an apocalyptic number.

It is an amenable number.

638780523261 is a deficient number, since it is larger than the sum of its proper divisors (259107273987).

638780523261 is a wasteful number, since it uses less digits than its factorization.

638780523261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146140672.

The product of its (nonzero) digits is 2903040, while the sum is 51.

The spelling of 638780523261 in words is "six hundred thirty-eight billion, seven hundred eighty million, five hundred twenty-three thousand, two hundred sixty-one".