21088229 has 4 divisors (see below), whose sum is σ = 21194400. Its totient is φ = 20982060.

The previous prime is 21088219. The next prime is 21088237. The reversal of 21088229 is 92288012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21088229 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21088195 and 21088204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21088219) 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 3 ways as a sum of consecutive naturals, for example, 52787 + ... + 53184.

It is an arithmetic number, because the mean of its divisors is an integer number (5298600).

Almost surely, 2^21088229 is an apocalyptic number.

It is an amenable number.

21088229 is a deficient number, since it is larger than the sum of its proper divisors (106171).

21088229 is a wasteful number, since it uses less digits than its factorization.

21088229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106170.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 21088229 is about 4592.1921780344. The cubic root of 21088229 is about 276.2782541756.

The spelling of 21088229 in words is "twenty-one million, eighty-eight thousand, two hundred twenty-nine".