66970921 has 2 divisors, whose sum is σ = 66970922. Its totient is φ = 66970920.

The previous prime is 66970901. The next prime is 66970949. The reversal of 66970921 is 12907966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49632025 + 17338896 = 7045^2 + 4164^2 .

It is a cyclic number.

It is not a de Polignac number, because 66970921 - 2⁷ = 66970793 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66970901) 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 as a sum of consecutive naturals, namely, 33485460 + 33485461.

It is an arithmetic number, because the mean of its divisors is an integer number (33485461).

Almost surely, 2^66970921 is an apocalyptic number.

It is an amenable number.

66970921 is a deficient number, since it is larger than the sum of its proper divisors (1).

66970921 is an equidigital number, since it uses as much as digits as its factorization.

66970921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 40.

The square root of 66970921 is about 8183.5762964611. The cubic root of 66970921 is about 406.0960424586.

The spelling of 66970921 in words is "sixty-six million, nine hundred seventy thousand, nine hundred twenty-one".