1666126291 has 2 divisors, whose sum is σ = 1666126292. Its totient is φ = 1666126290.

The previous prime is 1666126271. The next prime is 1666126309. The reversal of 1666126291 is 1926216661.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1666126291 - 2²⁵ = 1632571859 is a prime.

It is a super-2 number, since 2×1666126291² = 5551953635122833362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1666126261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833063145 + 833063146.

It is an arithmetic number, because the mean of its divisors is an integer number (833063146).

Almost surely, 2^1666126291 is an apocalyptic number.

1666126291 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666126291 is an equidigital number, since it uses as much as digits as its factorization.

1666126291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 40.

The square root of 1666126291 is about 40818.2102865865. The cubic root of 1666126291 is about 1185.5029504064.

The spelling of 1666126291 in words is "one billion, six hundred sixty-six million, one hundred twenty-six thousand, two hundred ninety-one".