660587261 has 2 divisors, whose sum is σ = 660587262. Its totient is φ = 660587260.

The previous prime is 660587251. The next prime is 660587287. The reversal of 660587261 is 162785066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 618467161 + 42120100 = 24869^2 + 6490^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-660587261 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 (660587251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330293630 + 330293631.

It is an arithmetic number, because the mean of its divisors is an integer number (330293631).

Almost surely, 2^660587261 is an apocalyptic number.

It is an amenable number.

660587261 is a deficient number, since it is larger than the sum of its proper divisors (1).

660587261 is an equidigital number, since it uses as much as digits as its factorization.

660587261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 41.

The square root of 660587261 is about 25701.8921676985. The cubic root of 660587261 is about 870.9169268766.

The spelling of 660587261 in words is "six hundred sixty million, five hundred eighty-seven thousand, two hundred sixty-one".