260561981 has 2 divisors, whose sum is σ = 260561982. Its totient is φ = 260561980.

The previous prime is 260561957. The next prime is 260562017. The reversal of 260561981 is 189165062.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 238084900 + 22477081 = 15430^2 + 4741^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-260561981 is a prime.

It is a super-2 number, since 2×260561981² = 135785091885288722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (260564981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130280990 + 130280991.

It is an arithmetic number, because the mean of its divisors is an integer number (130280991).

Almost surely, 2^260561981 is an apocalyptic number.

It is an amenable number.

260561981 is a deficient number, since it is larger than the sum of its proper divisors (1).

260561981 is an equidigital number, since it uses as much as digits as its factorization.

260561981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 260561981 is about 16141.9323812238. The cubic root of 260561981 is about 638.7099510355.

The spelling of 260561981 in words is "two hundred sixty million, five hundred sixty-one thousand, nine hundred eighty-one".