666227681 has 8 divisors (see below), whose sum is σ = 779110464. Its totient is φ = 557771760.

The previous prime is 666227669. The next prime is 666227687. The reversal of 666227681 is 186722666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 666227681 - 2¹⁸ = 665965537 is a prime.

It is a super-2 number, since 2×666227681² = 887718645861275522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (666227687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1106390 + ... + 1106991.

It is an arithmetic number, because the mean of its divisors is an integer number (97388808).

Almost surely, 2^666227681 is an apocalyptic number.

It is an amenable number.

666227681 is a deficient number, since it is larger than the sum of its proper divisors (112882783).

666227681 is a wasteful number, since it uses less digits than its factorization.

666227681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2213431.

The product of its digits is 290304, while the sum is 44.

The square root of 666227681 is about 25811.3866539557. The cubic root of 666227681 is about 873.3886779830.

It can be divided in two parts, 6662 and 27681, that added together give a palindrome (34343).

The spelling of 666227681 in words is "six hundred sixty-six million, two hundred twenty-seven thousand, six hundred eighty-one".