1661183816 has 8 divisors (see below), whose sum is σ = 3114719670. Its totient is φ = 830591904.

The previous prime is 1661183807. The next prime is 1661183819. The reversal of 1661183816 is 6183811661.

It can be written as a sum of positive squares in only one way, i.e., 1538992900 + 122190916 = 39230^2 + 11054^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (1661183819) 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, 103823981 + ... + 103823996.

Almost surely, 2^1661183816 is an apocalyptic number.

It is an amenable number.

1661183816 is a deficient number, since it is larger than the sum of its proper divisors (1453535854).

1661183816 is a wasteful number, since it uses less digits than its factorization.

1661183816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207647983 (or 207647979 counting only the distinct ones).

The product of its digits is 41472, while the sum is 41.

The square root of 1661183816 is about 40757.6227962329. The cubic root of 1661183816 is about 1184.3295455492.

The spelling of 1661183816 in words is "one billion, six hundred sixty-one million, one hundred eighty-three thousand, eight hundred sixteen".