966666581 has 2 divisors, whose sum is σ = 966666582. Its totient is φ = 966666580.

The previous prime is 966666559. The next prime is 966666587. The reversal of 966666581 is 185666669.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 699867025 + 266799556 = 26455^2 + 16334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-966666581 is a prime.

It is a super-4 number, since 4×966666581⁴ (a number of 37 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (966666587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 483333290 + 483333291.

It is an arithmetic number, because the mean of its divisors is an integer number (483333291).

Almost surely, 2^966666581 is an apocalyptic number.

It is an amenable number.

966666581 is a deficient number, since it is larger than the sum of its proper divisors (1).

966666581 is an equidigital number, since it uses as much as digits as its factorization.

966666581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2799360, while the sum is 53.

The square root of 966666581 is about 31091.2621326314. The cubic root of 966666581 is about 988.7630645734.

The spelling of 966666581 in words is "nine hundred sixty-six million, six hundred sixty-six thousand, five hundred eighty-one".