1666070621 has 2 divisors, whose sum is σ = 1666070622. Its totient is φ = 1666070620.

The previous prime is 1666070611. The next prime is 1666070663. The reversal of 1666070621 is 1260706661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1665537721 + 532900 = 40811^2 + 730^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666070621 - 2⁶ = 1666070557 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666070611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833035310 + 833035311.

It is an arithmetic number, because the mean of its divisors is an integer number (833035311).

Almost surely, 2^1666070621 is an apocalyptic number.

It is an amenable number.

1666070621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666070621 is an equidigital number, since it uses as much as digits as its factorization.

1666070621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 1666070621 is about 40817.5283548624. The cubic root of 1666070621 is about 1185.4897465885.

The spelling of 1666070621 in words is "one billion, six hundred sixty-six million, seventy thousand, six hundred twenty-one".