66149989 has 4 divisors (see below), whose sum is σ = 67398156. Its totient is φ = 64901824.

The previous prime is 66149983. The next prime is 66150017. The reversal of 66149989 is 98994166.

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 55800900 + 10349089 = 7470^2 + 3217^2 .

It is a cyclic number.

It is not a de Polignac number, because 66149989 - 2¹⁵ = 66117221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66149983) 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, 624004 + ... + 624109.

It is an arithmetic number, because the mean of its divisors is an integer number (16849539).

Almost surely, 2^66149989 is an apocalyptic number.

It is an amenable number.

66149989 is a deficient number, since it is larger than the sum of its proper divisors (1248167).

66149989 is a wasteful number, since it uses less digits than its factorization.

66149989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1248166.

The product of its digits is 839808, while the sum is 52.

The square root of 66149989 is about 8133.2643508004. The cubic root of 66149989 is about 404.4299025490.

The spelling of 66149989 in words is "sixty-six million, one hundred forty-nine thousand, nine hundred eighty-nine".