66638459738 has 8 divisors (see below), whose sum is σ = 103404506580. Its totient is φ = 32170290880.

The previous prime is 66638459729. The next prime is 66638459777. The reversal of 66638459738 is 83795483666.

It can be written as a sum of positive squares in 2 ways, for example, as 63682036609 + 2956423129 = 252353^2 + 54373^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 574469423 + ... + 574469538.

Almost surely, 2^66638459738 is an apocalyptic number.

66638459738 is a deficient number, since it is larger than the sum of its proper divisors (36766046842).

66638459738 is a wasteful number, since it uses less digits than its factorization.

66638459738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1148938992.

The product of its digits is 156764160, while the sum is 65.

The spelling of 66638459738 in words is "sixty-six billion, six hundred thirty-eight million, four hundred fifty-nine thousand, seven hundred thirty-eight".