21729341 has 2 divisors, whose sum is σ = 21729342. Its totient is φ = 21729340.

The previous prime is 21729329. The next prime is 21729361. The reversal of 21729341 is 14392712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16370116 + 5359225 = 4046^2 + 2315^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21729341 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21729361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10864670 + 10864671.

It is an arithmetic number, because the mean of its divisors is an integer number (10864671).

Almost surely, 2^21729341 is an apocalyptic number.

It is an amenable number.

21729341 is a deficient number, since it is larger than the sum of its proper divisors (1).

21729341 is an equidigital number, since it uses as much as digits as its factorization.

21729341 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 29.

The square root of 21729341 is about 4661.4741230645. The cubic root of 21729341 is about 279.0501016981.

The spelling of 21729341 in words is "twenty-one million, seven hundred twenty-nine thousand, three hundred forty-one".