998555281920 has 1280 divisors, whose sum is σ = 4302170357760. Its totient is φ = 214592716800.

The previous prime is 998555281909. The next prime is 998555281921. The reversal of 998555281920 is 29182555899.

998555281920 is a `hidden beast` number, since 9 + 9 + 85 + 5 + 528 + 1 + 9 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (1280).

It is a super-2 number, since 2×998555281920² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (998555281921) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 678826785 + ... + 678828255.

It is an arithmetic number, because the mean of its divisors is an integer number (3361070592).

Almost surely, 2^998555281920 is an apocalyptic number.

998555281920 is a gapful number since it is divisible by the number (90) 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 998555281920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2151085178880).

998555281920 is an abundant number, since it is smaller than the sum of its proper divisors (3303615075840).

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

998555281920 is a wasteful number, since it uses less digits than its factorization.

998555281920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1594 (or 1572 counting only the distinct ones).

The product of its (nonzero) digits is 23328000, while the sum is 63.

The spelling of 998555281920 in words is "nine hundred ninety-eight billion, five hundred fifty-five million, two hundred eighty-one thousand, nine hundred twenty".