1661985120 has 48 divisors (see below), whose sum is σ = 5235254640. Its totient is φ = 443195904.

The previous prime is 1661985047. The next prime is 1661985151. The reversal of 1661985120 is 215891661.

It is a tau number, because it is divible by the number of its divisors (48).

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, 1730755 + ... + 1731714.

It is an arithmetic number, because the mean of its divisors is an integer number (109067805).

Almost surely, 2^1661985120 is an apocalyptic number.

1661985120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1661985120 is an abundant number, since it is smaller than the sum of its proper divisors (3573269520).

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

1661985120 is a wasteful number, since it uses less digits than its factorization.

1661985120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3462487 (or 3462479 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 39.

The square root of 1661985120 is about 40767.4517231578. The cubic root of 1661985120 is about 1184.5199429921.

The spelling of 1661985120 in words is "one billion, six hundred sixty-one million, nine hundred eighty-five thousand, one hundred twenty".