1661803684 has 6 divisors (see below), whose sum is σ = 2908156454. Its totient is φ = 830901840.

The previous prime is 1661803603. The next prime is 1661803687. The reversal of 1661803684 is 4863081661.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1065369600 + 596434084 = 32640^2 + 24422^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1661803684.

It is not an unprimeable number, because it can be changed into a prime (1661803687) by changing a digit.

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 as a sum of consecutive naturals, namely, 207725457 + ... + 207725464.

Almost surely, 2^1661803684 is an apocalyptic number.

It is an amenable number.

1661803684 is a deficient number, since it is larger than the sum of its proper divisors (1246352770).

1661803684 is a wasteful number, since it uses less digits than its factorization.

1661803684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 415450925 (or 415450923 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 1661803684 is about 40765.2264068287. The cubic root of 1661803684 is about 1184.4768374354.

The spelling of 1661803684 in words is "one billion, six hundred sixty-one million, eight hundred three thousand, six hundred eighty-four".