638464863834 has 48 divisors (see below), whose sum is σ = 1664169074880. Its totient is φ = 172817556480.

The previous prime is 638464863821. The next prime is 638464863859. The reversal of 638464863834 is 438368464836.

638464863834 is a `hidden beast` number, since 6 + 38 + 46 + 486 + 3 + 83 + 4 = 666.

It is a super-2 number, since 2×638464863834² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 133344487 + ... + 133349274.

It is an arithmetic number, because the mean of its divisors is an integer number (34670189060).

Almost surely, 2^638464863834 is an apocalyptic number.

638464863834 is an abundant number, since it is smaller than the sum of its proper divisors (1025704211046).

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

638464863834 is a wasteful number, since it uses less digits than its factorization.

638464863834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266693795 (or 266693792 counting only the distinct ones).

The product of its digits is 191102976, while the sum is 63.

The spelling of 638464863834 in words is "six hundred thirty-eight billion, four hundred sixty-four million, eight hundred sixty-three thousand, eight hundred thirty-four".