21736229 has 2 divisors, whose sum is σ = 21736230. Its totient is φ = 21736228.

The previous prime is 21736189. The next prime is 21736237. The reversal of 21736229 is 92263712.

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., 19492225 + 2244004 = 4415^2 + 1498^2 .

It is a cyclic number.

It is not a de Polignac number, because 21736229 - 2²⁴ = 4959013 is a prime.

It is a super-2 number, since 2×21736229² = 944927302280882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21736195 and 21736204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21736259) 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 as a sum of consecutive naturals, namely, 10868114 + 10868115.

It is an arithmetic number, because the mean of its divisors is an integer number (10868115).

Almost surely, 2^21736229 is an apocalyptic number.

It is an amenable number.

21736229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21736229 is an equidigital number, since it uses as much as digits as its factorization.

21736229 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 32.

The square root of 21736229 is about 4662.2128866022. The cubic root of 21736229 is about 279.0795840164.

The spelling of 21736229 in words is "twenty-one million, seven hundred thirty-six thousand, two hundred twenty-nine".