66979823 has 2 divisors, whose sum is σ = 66979824. Its totient is φ = 66979822.

The previous prime is 66979799. The next prime is 66979873. The reversal of 66979823 is 32897966.

It is an a-pointer prime, because the next prime (66979873) can be obtained adding 66979823 to its sum of digits (50).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66979823 - 2¹⁰ = 66978799 is a prime.

It is a super-2 number, since 2×66979823² = 8972593378222658, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66979873) 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 as a sum of consecutive naturals, namely, 33489911 + 33489912.

It is an arithmetic number, because the mean of its divisors is an integer number (33489912).

Almost surely, 2^66979823 is an apocalyptic number.

66979823 is a deficient number, since it is larger than the sum of its proper divisors (1).

66979823 is an equidigital number, since it uses as much as digits as its factorization.

66979823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 50.

The square root of 66979823 is about 8184.1201726270. The cubic root of 66979823 is about 406.1140348785.

The spelling of 66979823 in words is "sixty-six million, nine hundred seventy-nine thousand, eight hundred twenty-three".