866654721 has 15 divisors (see below), whose sum is σ = 1295028273. Its totient is φ = 577593180.

The previous prime is 866654707. The next prime is 866654741. The reversal of 866654721 is 127456668.

The square root of 866654721 is 29439.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 866654721 - 2⁹ = 866654209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (866654741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 263316 + ... + 266586.

Almost surely, 2^866654721 is an apocalyptic number.

866654721 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

866654721 is the 29439-th square number.

866654721 is the 14720-th centered octagonal number.

It is an amenable number.

866654721 is a deficient number, since it is larger than the sum of its proper divisors (428373552).

866654721 is an frugal number, since it uses more digits than its factorization.

866654721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6554 (or 3274 counting only the distinct ones).

The product of its digits is 483840, while the sum is 45.

The cubic root of 866654721 is about 953.4151215006.

The spelling of 866654721 in words is "eight hundred sixty-six million, six hundred fifty-four thousand, seven hundred twenty-one".