638777837943 has 72 divisors (see below), whose sum is σ = 1087428526080. Its totient is φ = 360222539040.

The previous prime is 638777837939. The next prime is 638777837969. The reversal of 638777837943 is 349738777836.

It is not a de Polignac number, because 638777837943 - 2² = 638777837939 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638777847943) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 118136346 + ... + 118141752.

Almost surely, 2^638777837943 is an apocalyptic number.

638777837943 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

638777837943 is a deficient number, since it is larger than the sum of its proper divisors (448650688137).

638777837943 is a wasteful number, since it uses less digits than its factorization.

638777837943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8897 (or 8887 counting only the distinct ones).

The product of its digits is 896168448, while the sum is 72.

The spelling of 638777837943 in words is "six hundred thirty-eight billion, seven hundred seventy-seven million, eight hundred thirty-seven thousand, nine hundred forty-three".