1666535659 has 2 divisors, whose sum is σ = 1666535660. Its totient is φ = 1666535658.

The previous prime is 1666535621. The next prime is 1666535671. The reversal of 1666535659 is 9565356661.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1666535659 - 2⁹ = 1666535147 is a prime.

It is a super-2 number, since 2×1666535659² = 5554682205437128562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1666535609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833267829 + 833267830.

It is an arithmetic number, because the mean of its divisors is an integer number (833267830).

Almost surely, 2^1666535659 is an apocalyptic number.

1666535659 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666535659 is an equidigital number, since it uses as much as digits as its factorization.

1666535659 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4374000, while the sum is 52.

The square root of 1666535659 is about 40823.2245051760. The cubic root of 1666535659 is about 1185.6000353299.

The spelling of 1666535659 in words is "one billion, six hundred sixty-six million, five hundred thirty-five thousand, six hundred fifty-nine".