1666213535444 has 12 divisors (see below), whose sum is σ = 3009934128768. Its totient is φ = 806232355800.

The previous prime is 1666213535431. The next prime is 1666213535531. The reversal of 1666213535444 is 4445353126661.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1666213535392 and 1666213535401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6718602842 + ... + 6718603089.

It is an arithmetic number, because the mean of its divisors is an integer number (250827844064).

Almost surely, 2^{1666213535444} is an apocalyptic number.

It is an amenable number.

1666213535444 is a deficient number, since it is larger than the sum of its proper divisors (1343720593324).

1666213535444 is a wasteful number, since it uses less digits than its factorization.

1666213535444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13437205966 (or 13437205964 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 50.

The spelling of 1666213535444 in words is "one trillion, six hundred sixty-six billion, two hundred thirteen million, five hundred thirty-five thousand, four hundred forty-four".