21704700257 has 2 divisors, whose sum is σ = 21704700258. Its totient is φ = 21704700256.

The previous prime is 21704700247. The next prime is 21704700271. The reversal of 21704700257 is 75200740712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15726163216 + 5978537041 = 125404^2 + 77321^2 .

It is a cyclic number.

It is not a de Polignac number, because 21704700257 - 2¹⁸ = 21704438113 is a prime.

It is a super-3 number, since 3×21704700257³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21704700247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10852350128 + 10852350129.

It is an arithmetic number, because the mean of its divisors is an integer number (10852350129).

Almost surely, 2^21704700257 is an apocalyptic number.

It is an amenable number.

21704700257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21704700257 is an equidigital number, since it uses as much as digits as its factorization.

21704700257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27440, while the sum is 35.

The spelling of 21704700257 in words is "twenty-one billion, seven hundred four million, seven hundred thousand, two hundred fifty-seven".