1666843509258 has 24 divisors (see below), whose sum is σ = 3699579497796. Its totient is φ = 542062929600.

The previous prime is 1666843509251. The next prime is 1666843509313. The reversal of 1666843509258 is 8529053486661.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1665810979569 + 1032529689 = 1290663^2 + 32133^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1666843509195 and 1666843509204.

It is not an unprimeable number, because it can be changed into a prime (1666843509251) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1129297033 + ... + 1129298508.

Almost surely, 2^{1666843509258} is an apocalyptic number.

1666843509258 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1666843509258 is an abundant number, since it is smaller than the sum of its proper divisors (2032735988538).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1666843509258 is a wasteful number, since it uses less digits than its factorization.

1666843509258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2258595590 (or 2258595587 counting only the distinct ones).

The product of its (nonzero) digits is 74649600, while the sum is 63.

The spelling of 1666843509258 in words is "one trillion, six hundred sixty-six billion, eight hundred forty-three million, five hundred nine thousand, two hundred fifty-eight".