20981088 has 72 divisors (see below), whose sum is σ = 60108048. Its totient is φ = 6941952.

The previous prime is 20981069. The next prime is 20981089. The reversal of 20981088 is 88018902.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20981089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 75606 + ... + 75882.

It is an arithmetic number, because the mean of its divisors is an integer number (834834).

Almost surely, 2^20981088 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20981088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30054024).

20981088 is an abundant number, since it is smaller than the sum of its proper divisors (39126960).

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

20981088 is a wasteful number, since it uses less digits than its factorization.

20981088 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 556 (or 545 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 20981088 is about 4580.5117618013. The cubic root of 20981088 is about 275.8095724876.

The spelling of 20981088 in words is "twenty million, nine hundred eighty-one thousand, eighty-eight".