66631606 has 4 divisors (see below), whose sum is σ = 99947412. Its totient is φ = 33315802.

The previous prime is 66631603. The next prime is 66631633. The reversal of 66631606 is 60613666.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60613666 = 2 ⋅30306833.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66631603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16657900 + ... + 16657903.

It is an arithmetic number, because the mean of its divisors is an integer number (24986853).

Almost surely, 2^66631606 is an apocalyptic number.

66631606 is a deficient number, since it is larger than the sum of its proper divisors (33315806).

66631606 is a wasteful number, since it uses less digits than its factorization.

66631606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33315805.

The product of its (nonzero) digits is 23328, while the sum is 34.

The square root of 66631606 is about 8162.8185083340. The cubic root of 66631606 is about 405.4090385547.

The spelling of 66631606 in words is "sixty-six million, six hundred thirty-one thousand, six hundred six".