66780817351 has 2 divisors, whose sum is σ = 66780817352. Its totient is φ = 66780817350.

The previous prime is 66780817333. The next prime is 66780817381. The reversal of 66780817351 is 15371808766.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66780817351 - 2¹¹ = 66780815303 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66780817381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33390408675 + 33390408676.

It is an arithmetic number, because the mean of its divisors is an integer number (33390408676).

Almost surely, 2^66780817351 is an apocalyptic number.

66780817351 is a deficient number, since it is larger than the sum of its proper divisors (1).

66780817351 is an equidigital number, since it uses as much as digits as its factorization.

66780817351 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1693440, while the sum is 52.

The spelling of 66780817351 in words is "sixty-six billion, seven hundred eighty million, eight hundred seventeen thousand, three hundred fifty-one".