21051229 has 8 divisors (see below), whose sum is σ = 21746232. Its totient is φ = 20367360.

The previous prime is 21051203. The next prime is 21051241. The reversal of 21051229 is 92215012.

It can be written as a sum of positive squares in 4 ways, for example, as 7896100 + 13155129 = 2810^2 + 3627^2 .

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 21051229 - 2⁵ = 21051197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051029) 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, 1149 + ... + 6589.

It is an arithmetic number, because the mean of its divisors is an integer number (2718279).

Almost surely, 2^21051229 is an apocalyptic number.

It is an amenable number.

21051229 is a deficient number, since it is larger than the sum of its proper divisors (695003).

21051229 is an equidigital number, since it uses as much as digits as its factorization.

21051229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5567.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 21051229 is about 4588.1618323682. The cubic root of 21051229 is about 276.1165797854.

The spelling of 21051229 in words is "twenty-one million, fifty-one thousand, two hundred twenty-nine".