21088091 has 8 divisors (see below), whose sum is σ = 21995904. Its totient is φ = 20194560.

The previous prime is 21088087. The next prime is 21088141. The reversal of 21088091 is 19088012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21088091 - 2² = 21088087 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21088061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 500 + ... + 6513.

It is an arithmetic number, because the mean of its divisors is an integer number (2749488).

Almost surely, 2^21088091 is an apocalyptic number.

21088091 is a deficient number, since it is larger than the sum of its proper divisors (907813).

21088091 is an equidigital number, since it uses as much as digits as its factorization.

21088091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7141.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 21088091 is about 4592.1771525062. The cubic root of 21088091 is about 276.2776515253.

The spelling of 21088091 in words is "twenty-one million, eighty-eight thousand, ninety-one".