66989 has 4 divisors (see below), whose sum is σ = 72156. Its totient is φ = 61824.

The previous prime is 66977. The next prime is 67003. The reversal of 66989 is 98966.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 24964 + 42025 = 158^2 + 205^2 .

It is a cyclic number.

It is not a de Polignac number, because 66989 - 2⁴ = 66973 is a prime.

It is a super-2 number, since 2×66989² = 8975052242, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66919) 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, 2564 + ... + 2589.

It is an arithmetic number, because the mean of its divisors is an integer number (18039).

2⁶⁶⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

66989 is a deficient number, since it is larger than the sum of its proper divisors (5167).

66989 is a wasteful number, since it uses less digits than its factorization.

66989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5166.

The product of its digits is 23328, while the sum is 38.

The square root of 66989 is about 258.8223328849. The cubic root of 66989 is about 40.6132581450.

The spelling of 66989 in words is "sixty-six thousand, nine hundred eighty-nine".