21704357 has 2 divisors, whose sum is σ = 21704358. Its totient is φ = 21704356.

The previous prime is 21704351. The next prime is 21704369. The reversal of 21704357 is 75340712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19351201 + 2353156 = 4399^2 + 1534^2 .

It is a cyclic number.

It is not a de Polignac number, because 21704357 - 2⁸ = 21704101 is a prime.

It is a super-2 number, since 2×21704357² = 942158225566898, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21704351) 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, 10852178 + 10852179.

It is an arithmetic number, because the mean of its divisors is an integer number (10852179).

Almost surely, 2^21704357 is an apocalyptic number.

It is an amenable number.

21704357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21704357 is an equidigital number, since it uses as much as digits as its factorization.

21704357 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 21704357 is about 4658.7935133466. The cubic root of 21704357 is about 278.9431117767.

The spelling of 21704357 in words is "twenty-one million, seven hundred four thousand, three hundred fifty-seven".