66820000691 has 2 divisors, whose sum is σ = 66820000692. Its totient is φ = 66820000690.

The previous prime is 66820000673. The next prime is 66820000697. The reversal of 66820000691 is 19600002866.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66820000691 is a prime.

It is not a weakly prime, because it can be changed into another prime (66820000697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33410000345 + 33410000346.

It is an arithmetic number, because the mean of its divisors is an integer number (33410000346).

Almost surely, 2^66820000691 is an apocalyptic number.

66820000691 is a deficient number, since it is larger than the sum of its proper divisors (1).

66820000691 is an equidigital number, since it uses as much as digits as its factorization.

66820000691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 38.

The spelling of 66820000691 in words is "sixty-six billion, eight hundred twenty million, six hundred ninety-one", and thus it is an aban number.