66663081 has 10 divisors (see below), whose sum is σ = 99583242. Its totient is φ = 44442000.

The previous prime is 66663059. The next prime is 66663101. The reversal of 66663081 is 18036666.

It can be written as a sum of positive squares in only one way, i.e., 37015056 + 29648025 = 6084^2 + 5445^2 .

It is not a de Polignac number, because 66663081 - 2⁶ = 66663017 is a prime.

It is a super-2 number, since 2×66663081² = 8887932736825122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66663041) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 411420 + ... + 411581.

Almost surely, 2^66663081 is an apocalyptic number.

It is an amenable number.

66663081 is a deficient number, since it is larger than the sum of its proper divisors (32920161).

66663081 is an equidigital number, since it uses as much as digits as its factorization.

66663081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 823013 (or 823004 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 66663081 is about 8164.7462299817. The cubic root of 66663081 is about 405.4728633249.

The spelling of 66663081 in words is "sixty-six million, six hundred sixty-three thousand, eighty-one".