1666400180 has 24 divisors (see below), whose sum is σ = 3705290568. Its totient is φ = 627350528.

The previous prime is 1666400159. The next prime is 1666400207. The reversal of 1666400180 is 810046661.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 358420624 + 1307979556 = 18932^2 + 36166^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2450249 + ... + 2450928.

It is an arithmetic number, because the mean of its divisors is an integer number (154387107).

Almost surely, 2^1666400180 is an apocalyptic number.

1666400180 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666400180 is an abundant number, since it is smaller than the sum of its proper divisors (2038890388).

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

1666400180 is a wasteful number, since it uses less digits than its factorization.

1666400180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4901203 (or 4901201 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 1666400180 is about 40821.5651341298. The cubic root of 1666400180 is about 1185.5679071525.

The spelling of 1666400180 in words is "one billion, six hundred sixty-six million, four hundred thousand, one hundred eighty".