1998557140 has 12 divisors (see below), whose sum is σ = 4196970036. Its totient is φ = 799422848.

The previous prime is 1998557117. The next prime is 1998557149. The reversal of 1998557140 is 417558991.

It can be written as a sum of positive squares in 2 ways, for example, as 1167042244 + 831514896 = 34162^2 + 28836^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998557149) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49963909 + ... + 49963948.

It is an arithmetic number, because the mean of its divisors is an integer number (349747503).

Almost surely, 2^1998557140 is an apocalyptic number.

1998557140 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1998557140 is an abundant number, since it is smaller than the sum of its proper divisors (2198412896).

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

1998557140 is a wasteful number, since it uses less digits than its factorization.

1998557140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99927866 (or 99927864 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 49.

The square root of 1998557140 is about 44705.2249742689. The cubic root of 1998557140 is about 1259.6179953913.

The spelling of 1998557140 in words is "one billion, nine hundred ninety-eight million, five hundred fifty-seven thousand, one hundred forty".