66631967 has 4 divisors (see below), whose sum is σ = 66687936. Its totient is φ = 66576000.

The previous prime is 66631963. The next prime is 66631979. The reversal of 66631967 is 76913666.

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

It is a cyclic number.

It is not a de Polignac number, because 66631967 - 2² = 66631963 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 (66631963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26159 + ... + 28592.

It is an arithmetic number, because the mean of its divisors is an integer number (16671984).

Almost surely, 2^66631967 is an apocalyptic number.

66631967 is a deficient number, since it is larger than the sum of its proper divisors (55969).

66631967 is a wasteful number, since it uses less digits than its factorization.

66631967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55968.

The product of its digits is 244944, while the sum is 44.

The square root of 66631967 is about 8162.8406207643. The cubic root of 66631967 is about 405.4097707018.

The spelling of 66631967 in words is "sixty-six million, six hundred thirty-one thousand, nine hundred sixty-seven".