66981769 has 2 divisors, whose sum is σ = 66981770. Its totient is φ = 66981768.

The previous prime is 66981763. The next prime is 66981779. The reversal of 66981769 is 96718966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65804544 + 1177225 = 8112^2 + 1085^2 .

It is a cyclic number.

It is not a de Polignac number, because 66981769 - 2¹¹ = 66979721 is a prime.

It is a super-2 number, since 2×66981769² = 8973114756738722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66981763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33490884 + 33490885.

It is an arithmetic number, because the mean of its divisors is an integer number (33490885).

Almost surely, 2^66981769 is an apocalyptic number.

It is an amenable number.

66981769 is a deficient number, since it is larger than the sum of its proper divisors (1).

66981769 is an equidigital number, since it uses as much as digits as its factorization.

66981769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 52.

The square root of 66981769 is about 8184.2390605358. The cubic root of 66981769 is about 406.1179678553.

The spelling of 66981769 in words is "sixty-six million, nine hundred eighty-one thousand, seven hundred sixty-nine".