66766491 has 32 divisors (see below), whose sum is σ = 110557440. Its totient is φ = 39470400.

The previous prime is 66766481. The next prime is 66766501. The reversal of 66766491 is 19466766.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (66766481) and next prime (66766501).

It is not a de Polignac number, because 66766491 - 2¹³ = 66758299 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66766411) 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 31 ways as a sum of consecutive naturals, for example, 9436 + ... + 14918.

It is an arithmetic number, because the mean of its divisors is an integer number (3454920).

Almost surely, 2^66766491 is an apocalyptic number.

66766491 is a deficient number, since it is larger than the sum of its proper divisors (43790949).

66766491 is a wasteful number, since it uses less digits than its factorization.

66766491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5544 (or 5538 counting only the distinct ones).

The product of its digits is 326592, while the sum is 45.

The square root of 66766491 is about 8171.0764896677. The cubic root of 66766491 is about 405.6824160278.

The spelling of 66766491 in words is "sixty-six million, seven hundred sixty-six thousand, four hundred ninety-one".