21998386558938 has 8 divisors (see below), whose sum is σ = 43996773117888. Its totient is φ = 7332795519644.

The previous prime is 21998386558933. The next prime is 21998386558963. The reversal of 21998386558938 is 83985568389912.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

21998386558938 is an admirable number.

It is a super-2 number, since 2×21998386558938² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21998386558933) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1833198879906 + ... + 1833198879917.

It is an arithmetic number, because the mean of its divisors is an integer number (5499596639736).

Almost surely, 2^{21998386558938} is an apocalyptic number.

21998386558938 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21998386558938 is a wasteful number, since it uses less digits than its factorization.

21998386558938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3666397759828.

The product of its digits is 8062156800, while the sum is 84.

The spelling of 21998386558938 in words is "twenty-one trillion, nine hundred ninety-eight billion, three hundred eighty-six million, five hundred fifty-eight thousand, nine hundred thirty-eight".