638682113 has 2 divisors, whose sum is σ = 638682114. Its totient is φ = 638682112.

The previous prime is 638682073. The next prime is 638682137. The reversal of 638682113 is 311286836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 466862449 + 171819664 = 21607^2 + 13108^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638682113 is a prime.

It is a super-2 number, since 2×638682113² = 815829682932289538, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (638682313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319341056 + 319341057.

It is an arithmetic number, because the mean of its divisors is an integer number (319341057).

Almost surely, 2^638682113 is an apocalyptic number.

It is an amenable number.

638682113 is a deficient number, since it is larger than the sum of its proper divisors (1).

638682113 is an equidigital number, since it uses as much as digits as its factorization.

638682113 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 38.

The square root of 638682113 is about 25272.1608296560. The cubic root of 638682113 is about 861.1819483882.

The spelling of 638682113 in words is "six hundred thirty-eight million, six hundred eighty-two thousand, one hundred thirteen".