1998357678 has 24 divisors (see below), whose sum is σ = 4394401128. Its totient is φ = 656176752.

The previous prime is 1998357659. The next prime is 1998357689. The reversal of 1998357678 is 8767538991.

1998357678 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 827301 + ... + 829712.

It is an arithmetic number, because the mean of its divisors is an integer number (183100047).

Almost surely, 2^1998357678 is an apocalyptic number.

1998357678 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1998357678 is an abundant number, since it is smaller than the sum of its proper divisors (2396043450).

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

1998357678 is a wasteful number, since it uses less digits than its factorization.

1998357678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1657088 (or 1657085 counting only the distinct ones).

The product of its digits is 22861440, while the sum is 63.

The square root of 1998357678 is about 44702.9940608009. The cubic root of 1998357678 is about 1259.5760894452.

The spelling of 1998357678 in words is "one billion, nine hundred ninety-eight million, three hundred fifty-seven thousand, six hundred seventy-eight".