21138044088 has 128 divisors (see below), whose sum is σ = 62553254400. Its totient is φ = 5824068096.

The previous prime is 21138044077. The next prime is 21138044089. The reversal of 21138044088 is 88044083112.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21138044089) 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, 4933195 + ... + 4937477.

It is an arithmetic number, because the mean of its divisors is an integer number (488697300).

Almost surely, 2^21138044088 is an apocalyptic number.

21138044088 is a gapful number since it is divisible by the number (28) 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 21138044088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31276627200).

21138044088 is an abundant number, since it is smaller than the sum of its proper divisors (41415210312).

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

21138044088 is a wasteful number, since it uses less digits than its factorization.

21138044088 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5341 (or 5337 counting only the distinct ones).

The product of its (nonzero) digits is 49152, while the sum is 39.

The spelling of 21138044088 in words is "twenty-one billion, one hundred thirty-eight million, forty-four thousand, eighty-eight".