21704029 has 2 divisors, whose sum is σ = 21704030. Its totient is φ = 21704028.

The previous prime is 21704027. The next prime is 21704069. The reversal of 21704029 is 92040712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21178404 + 525625 = 4602^2 + 725^2 .

It is a cyclic number.

It is not a de Polignac number, because 21704029 - 2¹ = 21704027 is a prime.

Together with 21704027, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21703994 and 21704012.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21704027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10852014 + 10852015.

It is an arithmetic number, because the mean of its divisors is an integer number (10852015).

Almost surely, 2^21704029 is an apocalyptic number.

It is an amenable number.

21704029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21704029 is an equidigital number, since it uses as much as digits as its factorization.

21704029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21704029 is about 4658.7583109666. The cubic root of 21704029 is about 278.9417066241.

The spelling of 21704029 in words is "twenty-one million, seven hundred four thousand, twenty-nine".