66976639 has 2 divisors, whose sum is σ = 66976640. Its totient is φ = 66976638.

The previous prime is 66976627. The next prime is 66976669. The reversal of 66976639 is 93667966.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66976639 - 2⁹ = 66976127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66976619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33488319 + 33488320.

It is an arithmetic number, because the mean of its divisors is an integer number (33488320).

Almost surely, 2^66976639 is an apocalyptic number.

66976639 is a deficient number, since it is larger than the sum of its proper divisors (1).

66976639 is an equidigital number, since it uses as much as digits as its factorization.

66976639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2204496, while the sum is 52.

The square root of 66976639 is about 8183.9256472673. The cubic root of 66976639 is about 406.1075996690.

The spelling of 66976639 in words is "sixty-six million, nine hundred seventy-six thousand, six hundred thirty-nine".