66138994 has 8 divisors (see below), whose sum is σ = 99243180. Its totient is φ = 33057936.

The previous prime is 66138991. The next prime is 66138997. The reversal of 66138994 is 49983166.

It is an interprime number because it is at equal distance from previous prime (66138991) and next prime (66138997).

It can be written as a sum of positive squares in 2 ways, for example, as 59089969 + 7049025 = 7687^2 + 2655^2 .

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

It is not an unprimeable number, because it can be changed into a prime (66138991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7192 + ... + 13564.

Almost surely, 2^66138994 is an apocalyptic number.

66138994 is a deficient number, since it is larger than the sum of its proper divisors (33104186).

66138994 is a wasteful number, since it uses less digits than its factorization.

66138994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11564.

The product of its digits is 279936, while the sum is 46.

The square root of 66138994 is about 8132.5883948470. The cubic root of 66138994 is about 404.4074941141.

The spelling of 66138994 in words is "sixty-six million, one hundred thirty-eight thousand, nine hundred ninety-four".