21045229 has 2 divisors, whose sum is σ = 21045230. Its totient is φ = 21045228.

The previous prime is 21045197. The next prime is 21045239. The reversal of 21045229 is 92254012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18232900 + 2812329 = 4270^2 + 1677^2 .

It is a cyclic number.

It is not a de Polignac number, because 21045229 - 2⁵ = 21045197 is a prime.

It is equal to p_1332664 and since 21045229 and 1332664 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21045239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522614 + 10522615.

It is an arithmetic number, because the mean of its divisors is an integer number (10522615).

Almost surely, 2^21045229 is an apocalyptic number.

It is an amenable number.

21045229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21045229 is an equidigital number, since it uses as much as digits as its factorization.

21045229 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21045229 is about 4587.5079291485. The cubic root of 21045229 is about 276.0903444699.

The spelling of 21045229 in words is "twenty-one million, forty-five thousand, two hundred twenty-nine".