21081088 has 88 divisors (see below), whose sum is σ = 51289632. Its totient is φ = 8454144.

The previous prime is 21081061. The next prime is 21081101. The reversal of 21081088 is 88018012.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 121770 + ... + 121942.

Almost surely, 2^21081088 is an apocalyptic number.

21081088 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 21081088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25644816).

21081088 is an abundant number, since it is smaller than the sum of its proper divisors (30208544).

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

21081088 is a wasteful number, since it uses less digits than its factorization.

21081088 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217 (or 199 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 28.

The square root of 21081088 is about 4591.4145968318. The cubic root of 21081088 is about 276.2470657537.

The spelling of 21081088 in words is "twenty-one million, eighty-one thousand, eighty-eight".