66809701 has 16 divisors (see below), whose sum is σ = 79280640. Its totient is φ = 55111680.

The previous prime is 66809693. The next prime is 66809731. The reversal of 66809701 is 10790866.

It is a cyclic number.

It is not a de Polignac number, because 66809701 - 2³ = 66809693 is a prime.

It is a super-2 number, since 2×66809701² = 8927072295418802, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66809731) 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 15 ways as a sum of consecutive naturals, for example, 18405 + ... + 21733.

It is an arithmetic number, because the mean of its divisors is an integer number (4955040).

Almost surely, 2^66809701 is an apocalyptic number.

66809701 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

66809701 is a deficient number, since it is larger than the sum of its proper divisors (12470939).

66809701 is a wasteful number, since it uses less digits than its factorization.

66809701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3444.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 66809701 is about 8173.7201444630. The cubic root of 66809701 is about 405.7699137965.

The spelling of 66809701 in words is "sixty-six million, eight hundred nine thousand, seven hundred one".