1666449375 has 20 divisors (see below), whose sum is σ = 2776529976. Its totient is φ = 888772000.

The previous prime is 1666449371. The next prime is 1666449431. The reversal of 1666449375 is 5739446661.

It is not a de Polignac number, because 1666449375 - 2² = 1666449371 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666449371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 442512 + ... + 446261.

Almost surely, 2^1666449375 is an apocalyptic number.

1666449375 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1666449375 is a deficient number, since it is larger than the sum of its proper divisors (1110080601).

1666449375 is an frugal number, since it uses more digits than its factorization.

1666449375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 888796 (or 888781 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 51.

The square root of 1666449375 is about 40822.1676910965. The cubic root of 1666449375 is about 1185.5795737057.

The spelling of 1666449375 in words is "one billion, six hundred sixty-six million, four hundred forty-nine thousand, three hundred seventy-five".