66631658 has 4 divisors (see below), whose sum is σ = 99947490. Its totient is φ = 33315828.

The previous prime is 66631637. The next prime is 66631661. The reversal of 66631658 is 85613666.

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

It can be written as a sum of positive squares in only one way, i.e., 65723449 + 908209 = 8107^2 + 953^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16657913 + ... + 16657916.

Almost surely, 2^66631658 is an apocalyptic number.

66631658 is a deficient number, since it is larger than the sum of its proper divisors (33315832).

66631658 is a wasteful number, since it uses less digits than its factorization.

66631658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33315831.

The product of its digits is 155520, while the sum is 41.

The square root of 66631658 is about 8162.8216935077. The cubic root of 66631658 is about 405.4091440165.

The spelling of 66631658 in words is "sixty-six million, six hundred thirty-one thousand, six hundred fifty-eight".