1666195640 has 16 divisors (see below), whose sum is σ = 3748940280. Its totient is φ = 666478240.

The previous prime is 1666195639. The next prime is 1666195649. The reversal of 1666195640 is 465916661.

It is a junction number, because it is equal to n+sod(n) for n = 1666195591 and 1666195600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666195649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20827406 + ... + 20827485.

Almost surely, 2^1666195640 is an apocalyptic number.

1666195640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666195640 is an abundant number, since it is smaller than the sum of its proper divisors (2082744640).

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

1666195640 is a wasteful number, since it uses less digits than its factorization.

1666195640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41654902 (or 41654898 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 44.

The square root of 1666195640 is about 40819.0597637917. The cubic root of 1666195640 is about 1185.5193981999.

The spelling of 1666195640 in words is "one billion, six hundred sixty-six million, one hundred ninety-five thousand, six hundred forty".