638823846487 has 4 divisors (see below), whose sum is σ = 638833236696. Its totient is φ = 638814456280.

The previous prime is 638823846407. The next prime is 638823846571. The reversal of 638823846487 is 784648328836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638823846487 is a prime.

It is a super-2 number, since 2×638823846487² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638823846407) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4592308 + ... + 4729369.

It is an arithmetic number, because the mean of its divisors is an integer number (159708309174).

Almost surely, 2^638823846487 is an apocalyptic number.

638823846487 is a deficient number, since it is larger than the sum of its proper divisors (9390209).

638823846487 is an equidigital number, since it uses as much as digits as its factorization.

638823846487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9390208.

The product of its digits is 297271296, while the sum is 67.

The spelling of 638823846487 in words is "six hundred thirty-eight billion, eight hundred twenty-three million, eight hundred forty-six thousand, four hundred eighty-seven".