1661308188 has 12 divisors (see below), whose sum is σ = 3876385800. Its totient is φ = 553769392.

The previous prime is 1661308171. The next prime is 1661308213. The reversal of 1661308188 is 8818031661.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-3 number, since 3×1661308188³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69221163 + ... + 69221186.

It is an arithmetic number, because the mean of its divisors is an integer number (323032150).

Almost surely, 2^1661308188 is an apocalyptic number.

It is an amenable number.

1661308188 is an abundant number, since it is smaller than the sum of its proper divisors (2215077612).

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

1661308188 is a wasteful number, since it uses less digits than its factorization.

1661308188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138442356 (or 138442354 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 42.

The square root of 1661308188 is about 40759.1485190748. The cubic root of 1661308188 is about 1184.3591015314.

The spelling of 1661308188 in words is "one billion, six hundred sixty-one million, three hundred eight thousand, one hundred eighty-eight".