1661989844 has 12 divisors (see below), whose sum is σ = 3034938144. Its totient is φ = 794864664.

The previous prime is 1661989843. The next prime is 1661989871. The reversal of 1661989844 is 4489891661.

It is a self number, because there is not a number n which added to its sum of digits gives 1661989844.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661989843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9032462 + ... + 9032645.

It is an arithmetic number, because the mean of its divisors is an integer number (252911512).

Almost surely, 2^1661989844 is an apocalyptic number.

It is an amenable number.

1661989844 is a deficient number, since it is larger than the sum of its proper divisors (1372948300).

1661989844 is a wasteful number, since it uses less digits than its factorization.

1661989844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18065134 (or 18065132 counting only the distinct ones).

The product of its digits is 2985984, while the sum is 56.

The square root of 1661989844 is about 40767.5096614939. The cubic root of 1661989844 is about 1184.5210652779.

The spelling of 1661989844 in words is "one billion, six hundred sixty-one million, nine hundred eighty-nine thousand, eight hundred forty-four".