1985521800 has 96 divisors (see below), whose sum is σ = 6517216800. Its totient is φ = 498324480.

The previous prime is 1985521789. The next prime is 1985521807. The reversal of 1985521800 is 81255891.

It is not an unprimeable number, because it can be changed into a prime (1985521807) 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 in 23 ways as a sum of consecutive naturals, for example, 87130 + ... + 107529.

It is an arithmetic number, because the mean of its divisors is an integer number (67887675).

Almost surely, 2^1985521800 is an apocalyptic number.

1985521800 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1985521800 is an abundant number, since it is smaller than the sum of its proper divisors (4531695000).

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

1985521800 is a wasteful number, since it uses less digits than its factorization.

1985521800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194695 (or 194686 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 39.

The square root of 1985521800 is about 44559.1943374204. The cubic root of 1985521800 is about 1256.8734525770.

The spelling of 1985521800 in words is "one billion, nine hundred eighty-five million, five hundred twenty-one thousand, eight hundred".