638634470377 has 16 divisors (see below), whose sum is σ = 655679323152. Its totient is φ = 621661178880.

The previous prime is 638634470339. The next prime is 638634470437. The reversal of 638634470377 is 773074436836.

638634470377 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 8 ways, for example, as 147935621376 + 490698849001 = 384624^2 + 700499^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638634470377 is a prime.

It is a super-2 number, since 2×638634470377² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638634470777) 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, 34257703 + ... + 34276339.

It is an arithmetic number, because the mean of its divisors is an integer number (40979957697).

Almost surely, 2^638634470377 is an apocalyptic number.

It is an amenable number.

638634470377 is a deficient number, since it is larger than the sum of its proper divisors (17044852775).

638634470377 is a wasteful number, since it uses less digits than its factorization.

638634470377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20508.

The product of its (nonzero) digits is 42674688, while the sum is 58.

It can be divided in two parts, 638634 and 470377, that added together give a palindrome (1109011).

The spelling of 638634470377 in words is "six hundred thirty-eight billion, six hundred thirty-four million, four hundred seventy thousand, three hundred seventy-seven".