638724587 has 2 divisors, whose sum is σ = 638724588. Its totient is φ = 638724586.

The previous prime is 638724563. The next prime is 638724637. The reversal of 638724587 is 785427836.

It is an a-pointer prime, because the next prime (638724637) can be obtained adding 638724587 to its sum of digits (50).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638724587 - 2¹⁶ = 638659051 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (638724517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319362293 + 319362294.

It is an arithmetic number, because the mean of its divisors is an integer number (319362294).

Almost surely, 2^638724587 is an apocalyptic number.

638724587 is a deficient number, since it is larger than the sum of its proper divisors (1).

638724587 is an equidigital number, since it uses as much as digits as its factorization.

638724587 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2257920, while the sum is 50.

The square root of 638724587 is about 25273.0011474696. The cubic root of 638724587 is about 861.2010382351.

The spelling of 638724587 in words is "six hundred thirty-eight million, seven hundred twenty-four thousand, five hundred eighty-seven".