66808501 has 2 divisors, whose sum is σ = 66808502. Its totient is φ = 66808500.

The previous prime is 66808499. The next prime is 66808519. The reversal of 66808501 is 10580866.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48094225 + 18714276 = 6935^2 + 4326^2 .

It is a cyclic number.

It is not a de Polignac number, because 66808501 - 2¹ = 66808499 is a prime.

Together with 66808499, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66808531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33404250 + 33404251.

It is an arithmetic number, because the mean of its divisors is an integer number (33404251).

Almost surely, 2^66808501 is an apocalyptic number.

It is an amenable number.

66808501 is a deficient number, since it is larger than the sum of its proper divisors (1).

66808501 is an equidigital number, since it uses as much as digits as its factorization.

66808501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 66808501 is about 8173.6467381457. The cubic root of 66808501 is about 405.7674843748.

The spelling of 66808501 in words is "sixty-six million, eight hundred eight thousand, five hundred one".