3998891820 has 384 divisors, whose sum is σ = 14436237312. Its totient is φ = 803174400.

The previous prime is 3998891801. The next prime is 3998891837. The reversal of 3998891820 is 281988993.

It is a super-2 number, since 2×3998891820² = 31982271576125824800, which contains 22 as substring.

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 127 ways as a sum of consecutive naturals, for example, 23945377 + ... + 23945543.

It is an arithmetic number, because the mean of its divisors is an integer number (37594368).

Almost surely, 2^3998891820 is an apocalyptic number.

3998891820 is a gapful number since it is divisible by the number (30) 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 3998891820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7218118656).

3998891820 is an abundant number, since it is smaller than the sum of its proper divisors (10437345492).

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

3998891820 is a wasteful number, since it uses less digits than its factorization.

3998891820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 341 (or 339 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 57.

The square root of 3998891820 is about 63236.7916643468. The cubic root of 3998891820 is about 1587.2544445869.

The spelling of 3998891820 in words is "three billion, nine hundred ninety-eight million, eight hundred ninety-one thousand, eight hundred twenty".