1998939540 has 192 divisors, whose sum is σ = 6164121600. Its totient is φ = 481061376.

The previous prime is 1998939511. The next prime is 1998939557. The reversal of 1998939540 is 459398991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11167171 + ... + 11167349.

It is an arithmetic number, because the mean of its divisors is an integer number (32104800).

Almost surely, 2^1998939540 is an apocalyptic number.

1998939540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1998939540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3082060800).

1998939540 is an abundant number, since it is smaller than the sum of its proper divisors (4165182060).

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

1998939540 is a wasteful number, since it uses less digits than its factorization.

1998939540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446 (or 444 counting only the distinct ones).

The product of its (nonzero) digits is 3149280, while the sum is 57.

The square root of 1998939540 is about 44709.5016747000. The cubic root of 1998939540 is about 1259.6983278795.

The spelling of 1998939540 in words is "one billion, nine hundred ninety-eight million, nine hundred thirty-nine thousand, five hundred forty".