21171988332 has 96 divisors (see below), whose sum is σ = 60619910400. Its totient is φ = 6415724880.

The previous prime is 21171988297. The next prime is 21171988333. The reversal of 21171988332 is 23388917112.

It is not an unprimeable number, because it can be changed into a prime (21171988333) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13782 + ... + 206237.

It is an arithmetic number, because the mean of its divisors is an integer number (631457400).

Almost surely, 2^21171988332 is an apocalyptic number.

21171988332 is a gapful number since it is divisible by the number (22) 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 21171988332, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30309955200).

21171988332 is an abundant number, since it is smaller than the sum of its proper divisors (39447922068).

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

21171988332 is a wasteful number, since it uses less digits than its factorization.

21171988332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220055 (or 220035 counting only the distinct ones).

The product of its digits is 145152, while the sum is 45.

The spelling of 21171988332 in words is "twenty-one billion, one hundred seventy-one million, nine hundred eighty-eight thousand, three hundred thirty-two".