1666389447 has 12 divisors (see below), whose sum is σ = 2409949464. Its totient is φ = 1109568240.

The previous prime is 1666389443. The next prime is 1666389463. The reversal of 1666389447 is 7449836661.

It is not a de Polignac number, because 1666389447 - 2² = 1666389443 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1666389393 and 1666389402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666389443) 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, 105373 + ... + 120150.

It is an arithmetic number, because the mean of its divisors is an integer number (200829122).

Almost surely, 2^1666389447 is an apocalyptic number.

1666389447 is a deficient number, since it is larger than the sum of its proper divisors (743560017).

1666389447 is a wasteful number, since it uses less digits than its factorization.

1666389447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226350 (or 226347 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 54.

The square root of 1666389447 is about 40821.4336715407. The cubic root of 1666389447 is about 1185.5653617999.

The spelling of 1666389447 in words is "one billion, six hundred sixty-six million, three hundred eighty-nine thousand, four hundred forty-seven".