66600649 has 4 divisors (see below), whose sum is σ = 66620880. Its totient is φ = 66580420.

The previous prime is 66600631. The next prime is 66600671. The reversal of 66600649 is 94600666.

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: 94600666 = 2 ⋅47300333.

It is a cyclic number.

It is not a de Polignac number, because 66600649 - 2⁹ = 66600137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66600049) 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, 3907 + ... + 12184.

It is an arithmetic number, because the mean of its divisors is an integer number (16655220).

Almost surely, 2^66600649 is an apocalyptic number.

It is an amenable number.

66600649 is a deficient number, since it is larger than the sum of its proper divisors (20231).

66600649 is a wasteful number, since it uses less digits than its factorization.

66600649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20230.

The product of its (nonzero) digits is 46656, while the sum is 37.

The square root of 66600649 is about 8160.9220680019. The cubic root of 66600649 is about 405.3462445722.

The spelling of 66600649 in words is "sixty-six million, six hundred thousand, six hundred forty-nine".