684257261 has 2 divisors, whose sum is σ = 684257262. Its totient is φ = 684257260.

The previous prime is 684257227. The next prime is 684257369. The reversal of 684257261 is 162752486.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 448634761 + 235622500 = 21181^2 + 15350^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-684257261 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 (684257221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342128630 + 342128631.

It is an arithmetic number, because the mean of its divisors is an integer number (342128631).

Almost surely, 2^684257261 is an apocalyptic number.

It is an amenable number.

684257261 is a deficient number, since it is larger than the sum of its proper divisors (1).

684257261 is an equidigital number, since it uses as much as digits as its factorization.

684257261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 161280, while the sum is 41.

The square root of 684257261 is about 26158.3115089640. The cubic root of 684257261 is about 881.1972602544.

The spelling of 684257261 in words is "six hundred eighty-four million, two hundred fifty-seven thousand, two hundred sixty-one".