204257713721 has 2 divisors, whose sum is σ = 204257713722. Its totient is φ = 204257713720.

The previous prime is 204257713669. The next prime is 204257713811. The reversal of 204257713721 is 127317752402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133162957225 + 71094756496 = 364915^2 + 266636^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-204257713721 is a prime.

It is a super-2 number, since 2×204257713721² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (204257713321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102128856860 + 102128856861.

It is an arithmetic number, because the mean of its divisors is an integer number (102128856861).

Almost surely, 2^204257713721 is an apocalyptic number.

It is an amenable number.

204257713721 is a deficient number, since it is larger than the sum of its proper divisors (1).

204257713721 is an equidigital number, since it uses as much as digits as its factorization.

204257713721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 164640, while the sum is 41.

The spelling of 204257713721 in words is "two hundred four billion, two hundred fifty-seven million, seven hundred thirteen thousand, seven hundred twenty-one".