1666475640 has 64 divisors (see below), whose sum is σ = 5554922400. Its totient is φ = 444393216.

The previous prime is 1666475639. The next prime is 1666475641. The reversal of 1666475640 is 465746661.

It is an interprime number because it is at equal distance from previous prime (1666475639) and next prime (1666475641).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666475641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 770437 + ... + 772596.

Almost surely, 2^1666475640 is an apocalyptic number.

1666475640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666475640 is an abundant number, since it is smaller than the sum of its proper divisors (3888446760).

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

1666475640 is a wasteful number, since it uses less digits than its factorization.

1666475640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1543053 (or 1543043 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The square root of 1666475640 is about 40822.4893900409. The cubic root of 1666475640 is about 1185.5858023345.

The spelling of 1666475640 in words is "one billion, six hundred sixty-six million, four hundred seventy-five thousand, six hundred forty".