1666427740 has 48 divisors (see below), whose sum is σ = 3662184960. Its totient is φ = 635750720.

The previous prime is 1666427731. The next prime is 1666427743. The reversal of 1666427740 is 477246661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666427743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 160095 + ... + 170185.

It is an arithmetic number, because the mean of its divisors is an integer number (76295520).

Almost surely, 2^1666427740 is an apocalyptic number.

1666427740 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1666427740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1831092480).

1666427740 is an abundant number, since it is smaller than the sum of its proper divisors (1995757220).

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

1666427740 is a wasteful number, since it uses less digits than its factorization.

1666427740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10482 (or 10480 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 43.

The square root of 1666427740 is about 40821.9026994088. The cubic root of 1666427740 is about 1185.5744430118.

The spelling of 1666427740 in words is "one billion, six hundred sixty-six million, four hundred twenty-seven thousand, seven hundred forty".