1998505660 has 24 divisors (see below), whose sum is σ = 4249990080. Its totient is φ = 789282624.

The previous prime is 1998505651. The next prime is 1998505757. The reversal of 1998505660 is 665058991.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 630859 + ... + 634018.

It is an arithmetic number, because the mean of its divisors is an integer number (177082920).

Almost surely, 2^1998505660 is an apocalyptic number.

1998505660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1998505660 is an abundant number, since it is smaller than the sum of its proper divisors (2251484420).

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

1998505660 is a wasteful number, since it uses less digits than its factorization.

1998505660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1264965 (or 1264963 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 49.

The square root of 1998505660 is about 44704.6491989368. The cubic root of 1998505660 is about 1259.6071799735.

The spelling of 1998505660 in words is "one billion, nine hundred ninety-eight million, five hundred five thousand, six hundred sixty".