21442229 has 2 divisors, whose sum is σ = 21442230. Its totient is φ = 21442228.

The previous prime is 21442163. The next prime is 21442243. The reversal of 21442229 is 92224412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21436900 + 5329 = 4630^2 + 73^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21442229 is a prime.

It is equal to p_1356137 and since 21442229 and 1356137 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21442198 and 21442207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21441229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721114 + 10721115.

It is an arithmetic number, because the mean of its divisors is an integer number (10721115).

Almost surely, 2^21442229 is an apocalyptic number.

It is an amenable number.

21442229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21442229 is an equidigital number, since it uses as much as digits as its factorization.

21442229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 26.

The square root of 21442229 is about 4630.5754502005. The cubic root of 21442229 is about 277.8156093125.

The spelling of 21442229 in words is "twenty-one million, four hundred forty-two thousand, two hundred twenty-nine".