1166670721 has 2 divisors, whose sum is σ = 1166670722. Its totient is φ = 1166670720.

The previous prime is 1166670719. The next prime is 1166670727. The reversal of 1166670721 is 1270766611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1165266496 + 1404225 = 34136^2 + 1185^2 .

It is a cyclic number.

It is not a de Polignac number, because 1166670721 - 2¹ = 1166670719 is a prime.

It is a super-2 number, since 2×1166670721² = 2722241142477319682, which contains 22 as substring.

Together with 1166670719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1166670727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 583335360 + 583335361.

It is an arithmetic number, because the mean of its divisors is an integer number (583335361).

Almost surely, 2^1166670721 is an apocalyptic number.

It is an amenable number.

1166670721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1166670721 is an equidigital number, since it uses as much as digits as its factorization.

1166670721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 1166670721 is about 34156.5619025100. The cubic root of 1166670721 is about 1052.7278190664.

The spelling of 1166670721 in words is "one billion, one hundred sixty-six million, six hundred seventy thousand, seven hundred twenty-one".