66931289 has 2 divisors, whose sum is σ = 66931290. Its totient is φ = 66931288.

The previous prime is 66931279. The next prime is 66931301. The reversal of 66931289 is 98213966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50055625 + 16875664 = 7075^2 + 4108^2 .

It is a cyclic number.

It is not a de Polignac number, because 66931289 - 2⁴ = 66931273 is a prime.

It is not a weakly prime, because it can be changed into another prime (66931259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33465644 + 33465645.

It is an arithmetic number, because the mean of its divisors is an integer number (33465645).

Almost surely, 2^66931289 is an apocalyptic number.

It is an amenable number.

66931289 is a deficient number, since it is larger than the sum of its proper divisors (1).

66931289 is an equidigital number, since it uses as much as digits as its factorization.

66931289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 44.

The square root of 66931289 is about 8181.1545028804. The cubic root of 66931289 is about 406.0159202506.

The spelling of 66931289 in words is "sixty-six million, nine hundred thirty-one thousand, two hundred eighty-nine".