66406849 has 4 divisors (see below), whose sum is σ = 67398064. Its totient is φ = 65415636.

The previous prime is 66406841. The next prime is 66406853. The reversal of 66406849 is 94860466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 94860466 = 2 ⋅47430233.

It is a cyclic number.

It is not a de Polignac number, because 66406849 - 2³ = 66406841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66406841) 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, 495507 + ... + 495640.

It is an arithmetic number, because the mean of its divisors is an integer number (16849516).

Almost surely, 2^66406849 is an apocalyptic number.

It is an amenable number.

66406849 is a deficient number, since it is larger than the sum of its proper divisors (991215).

66406849 is an equidigital number, since it uses as much as digits as its factorization.

66406849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 991214.

The product of its (nonzero) digits is 248832, while the sum is 43.

The square root of 66406849 is about 8149.0397593827. The cubic root of 66406849 is about 404.9526927419.

The spelling of 66406849 in words is "sixty-six million, four hundred six thousand, eight hundred forty-nine".