638651534 has 16 divisors (see below), whose sum is σ = 1000194048. Its totient is φ = 305269272.

The previous prime is 638651411. The next prime is 638651539. The reversal of 638651534 is 435156836.

It is a junction number, because it is equal to n+sod(n) for n = 638651491 and 638651500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638651539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121019 + ... + 126185.

It is an arithmetic number, because the mean of its divisors is an integer number (62512128).

Almost surely, 2^638651534 is an apocalyptic number.

638651534 is a deficient number, since it is larger than the sum of its proper divisors (361542514).

638651534 is a wasteful number, since it uses less digits than its factorization.

638651534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7879.

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

The square root of 638651534 is about 25271.5558286386. Note that the first 3 decimals coincide. The cubic root of 638651534 is about 861.1682041991.

The spelling of 638651534 in words is "six hundred thirty-eight million, six hundred fifty-one thousand, five hundred thirty-four".