638928007 has 2 divisors, whose sum is σ = 638928008. Its totient is φ = 638928006.

The previous prime is 638927981. The next prime is 638928019. The reversal of 638928007 is 700829836.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 638928007 - 2¹⁹ = 638403719 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638928907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319464003 + 319464004.

It is an arithmetic number, because the mean of its divisors is an integer number (319464004).

Almost surely, 2^638928007 is an apocalyptic number.

638928007 is a deficient number, since it is larger than the sum of its proper divisors (1).

638928007 is an equidigital number, since it uses as much as digits as its factorization.

638928007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 638928007 is about 25277.0252798861. The cubic root of 638928007 is about 861.2924531811.

The spelling of 638928007 in words is "six hundred thirty-eight million, nine hundred twenty-eight thousand, seven".