66733691 has 4 divisors (see below), whose sum is σ = 68361384. Its totient is φ = 65106000.

The previous prime is 66733663. The next prime is 66733697. The reversal of 66733691 is 19633766.

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 66733691 - 2²² = 62539387 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41), and also a Moran number because the ratio is a prime number: 1627651 = 66733691 / (6 + 6 + 7 + 3 + 3 + 6 + 9 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66733697) 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, 813785 + ... + 813866.

It is an arithmetic number, because the mean of its divisors is an integer number (17090346).

Almost surely, 2^66733691 is an apocalyptic number.

66733691 is a deficient number, since it is larger than the sum of its proper divisors (1627693).

66733691 is a wasteful number, since it uses less digits than its factorization.

66733691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1627692.

The product of its digits is 122472, while the sum is 41.

The square root of 66733691 is about 8169.0691636196. The cubic root of 66733691 is about 405.6159727036.

The spelling of 66733691 in words is "sixty-six million, seven hundred thirty-three thousand, six hundred ninety-one".