66761691 has 8 divisors (see below), whose sum is σ = 89133840. Its totient is φ = 44448672.

The previous prime is 66761657. The next prime is 66761713. The reversal of 66761691 is 19616766.

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

It is not a de Polignac number, because 66761691 - 2⁹ = 66761179 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66761621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12076 + ... + 16713.

It is an arithmetic number, because the mean of its divisors is an integer number (11141730).

Almost surely, 2^66761691 is an apocalyptic number.

66761691 is a deficient number, since it is larger than the sum of its proper divisors (22372149).

66761691 is a wasteful number, since it uses less digits than its factorization.

66761691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29565.

The product of its digits is 81648, while the sum is 42.

The square root of 66761691 is about 8170.7827654393. The cubic root of 66761691 is about 405.6726939739.

The spelling of 66761691 in words is "sixty-six million, seven hundred sixty-one thousand, six hundred ninety-one".