21001088 has 16 divisors (see below), whose sum is σ = 41838360. Its totient is φ = 10500480.

The previous prime is 21001087. The next prime is 21001117. The reversal of 21001088 is 88010012.

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81908 + ... + 82163.

Almost surely, 2^21001088 is an apocalyptic number.

It is an amenable number.

21001088 is a deficient number, since it is larger than the sum of its proper divisors (20837272).

21001088 is an equidigital number, since it uses as much as digits as its factorization.

21001088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164085 (or 164073 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 21001088 is about 4582.6944039506. The cubic root of 21001088 is about 275.8971821741.

The spelling of 21001088 in words is "twenty-one million, one thousand, eighty-eight".