638543156 has 6 divisors (see below), whose sum is σ = 1117450530. Its totient is φ = 319271576.

The previous prime is 638543131. The next prime is 638543159. The reversal of 638543156 is 651345836.

It can be written as a sum of positive squares in only one way, i.e., 519384100 + 119159056 = 22790^2 + 10916^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638543159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79817891 + ... + 79817898.

It is an arithmetic number, because the mean of its divisors is an integer number (186241755).

Almost surely, 2^638543156 is an apocalyptic number.

It is an amenable number.

638543156 is a deficient number, since it is larger than the sum of its proper divisors (478907374).

638543156 is a wasteful number, since it uses less digits than its factorization.

638543156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159635793 (or 159635791 counting only the distinct ones).

The product of its digits is 259200, while the sum is 41.

The square root of 638543156 is about 25269.4114692052. The cubic root of 638543156 is about 861.1194885524.

The spelling of 638543156 in words is "six hundred thirty-eight million, five hundred forty-three thousand, one hundred fifty-six".