721666027 has 4 divisors (see below), whose sum is σ = 730801120. Its totient is φ = 712530936.

The previous prime is 721666021. The next prime is 721666063. The reversal of 721666027 is 720666127.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721666027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721666021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4567428 + ... + 4567585.

It is an arithmetic number, because the mean of its divisors is an integer number (182700280).

Almost surely, 2^721666027 is an apocalyptic number.

721666027 is a deficient number, since it is larger than the sum of its proper divisors (9135093).

721666027 is an equidigital number, since it uses as much as digits as its factorization.

721666027 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9135092.

The product of its (nonzero) digits is 42336, while the sum is 37.

The square root of 721666027 is about 26863.8423722296. The cubic root of 721666027 is about 896.9717261630.

The spelling of 721666027 in words is "seven hundred twenty-one million, six hundred sixty-six thousand, twenty-seven".