718661 has 2 divisors, whose sum is σ = 718662. Its totient is φ = 718660.

The previous prime is 718657. The next prime is 718691. The reversal of 718661 is 166817.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 532900 + 185761 = 730^2 + 431^2 .

It is a cyclic number.

It is not a de Polignac number, because 718661 - 2² = 718657 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 718661.

It is not a weakly prime, because it can be changed into another prime (718621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 359330 + 359331.

It is an arithmetic number, because the mean of its divisors is an integer number (359331).

2⁷¹⁸⁶⁶¹ is an apocalyptic number.

It is an amenable number.

718661 is a deficient number, since it is larger than the sum of its proper divisors (1).

718661 is an equidigital number, since it uses as much as digits as its factorization.

718661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016, while the sum is 29.

The square root of 718661 is about 847.7387569293. The cubic root of 718661 is about 89.5724993328.

The spelling of 718661 in words is "seven hundred eighteen thousand, six hundred sixty-one".