638104729 has 2 divisors, whose sum is σ = 638104730. Its totient is φ = 638104728.

The previous prime is 638104697. The next prime is 638104757. The reversal of 638104729 is 927401836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 324000000 + 314104729 = 18000^2 + 17723^2 .

It is a cyclic number.

It is not a de Polignac number, because 638104729 - 2⁵ = 638104697 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638104691 and 638104700.

It is not a weakly prime, because it can be changed into another prime (638101729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319052364 + 319052365.

It is an arithmetic number, because the mean of its divisors is an integer number (319052365).

Almost surely, 2^638104729 is an apocalyptic number.

It is an amenable number.

638104729 is a deficient number, since it is larger than the sum of its proper divisors (1).

638104729 is an equidigital number, since it uses as much as digits as its factorization.

638104729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 638104729 is about 25260.7349259676. The cubic root of 638104729 is about 860.9223604126.

The spelling of 638104729 in words is "six hundred thirty-eight million, one hundred four thousand, seven hundred twenty-nine".