66888139 has 2 divisors, whose sum is σ = 66888140. Its totient is φ = 66888138.

The previous prime is 66888137. The next prime is 66888169. The reversal of 66888139 is 93188866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66888139 - 2¹ = 66888137 is a prime.

Together with 66888137, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 66888092 and 66888101.

It is not a weakly prime, because it can be changed into another prime (66888137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33444069 + 33444070.

It is an arithmetic number, because the mean of its divisors is an integer number (33444070).

Almost surely, 2^66888139 is an apocalyptic number.

66888139 is a deficient number, since it is larger than the sum of its proper divisors (1).

66888139 is an equidigital number, since it uses as much as digits as its factorization.

66888139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 497664, while the sum is 49.

The square root of 66888139 is about 8178.5169193442. The cubic root of 66888139 is about 405.9286498898.

The spelling of 66888139 in words is "sixty-six million, eight hundred eighty-eight thousand, one hundred thirty-nine".