1985665220 has 72 divisors (see below), whose sum is σ = 5291697600. Its totient is φ = 618905280.

The previous prime is 1985665181. The next prime is 1985665249. The reversal of 1985665220 is 225665891.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 81320 + ... + 102879.

It is an arithmetic number, because the mean of its divisors is an integer number (73495800).

Almost surely, 2^1985665220 is an apocalyptic number.

1985665220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1985665220 is an abundant number, since it is smaller than the sum of its proper divisors (3306032380).

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

1985665220 is a wasteful number, since it uses less digits than its factorization.

1985665220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184233 (or 184224 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 44.

The square root of 1985665220 is about 44560.8036283010. The cubic root of 1985665220 is about 1256.9037143870.

The spelling of 1985665220 in words is "one billion, nine hundred eighty-five million, six hundred sixty-five thousand, two hundred twenty".