1666429 has 2 divisors, whose sum is σ = 1666430. Its totient is φ = 1666428.

The previous prime is 1666421. The next prime is 1666447. The reversal of 1666429 is 9246661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1625625 + 40804 = 1275^2 + 202^2 .

It is an emirp because it is prime and its reverse (9246661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1666429 - 2³ = 1666421 is a prime.

It is a super-2 number, since 2×1666429² = 5553971224082, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1666394 and 1666403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833214 + 833215.

It is an arithmetic number, because the mean of its divisors is an integer number (833215).

2^1666429 is an apocalyptic number.

It is an amenable number.

1666429 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666429 is an equidigital number, since it uses as much as digits as its factorization.

1666429 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 34.

The square root of 1666429 is about 1290.9023975499. The cubic root of 1666429 is about 118.5574741819.

The spelling of 1666429 in words is "one million, six hundred sixty-six thousand, four hundred twenty-nine".