66967691 has 8 divisors (see below), whose sum is σ = 77789664. Its totient is φ = 56459520.

The previous prime is 66967643. The next prime is 66967711. The reversal of 66967691 is 19676966.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66967691 - 2¹⁸ = 66705547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66967091) 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 7 ways as a sum of consecutive naturals, for example, 77990 + ... + 78843.

It is an arithmetic number, because the mean of its divisors is an integer number (9723708).

Almost surely, 2^66967691 is an apocalyptic number.

66967691 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

66967691 is a deficient number, since it is larger than the sum of its proper divisors (10821973).

66967691 is a wasteful number, since it uses less digits than its factorization.

66967691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156901.

The product of its digits is 734832, while the sum is 50.

The square root of 66967691 is about 8183.3789475986. The cubic root of 66967691 is about 406.0895136981.

The spelling of 66967691 in words is "sixty-six million, nine hundred sixty-seven thousand, six hundred ninety-one".