638242147 has 2 divisors, whose sum is σ = 638242148. Its totient is φ = 638242146.

The previous prime is 638242141. The next prime is 638242151. The reversal of 638242147 is 741242836.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638242147 is a prime.

It is not a weakly prime, because it can be changed into another prime (638242141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319121073 + 319121074.

It is an arithmetic number, because the mean of its divisors is an integer number (319121074).

Almost surely, 2^638242147 is an apocalyptic number.

638242147 is a deficient number, since it is larger than the sum of its proper divisors (1).

638242147 is an equidigital number, since it uses as much as digits as its factorization.

638242147 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64512, while the sum is 37.

The square root of 638242147 is about 25263.4547716657. The cubic root of 638242147 is about 860.9841568190.

The spelling of 638242147 in words is "six hundred thirty-eight million, two hundred forty-two thousand, one hundred forty-seven".