661717141 has 2 divisors, whose sum is σ = 661717142. Its totient is φ = 661717140.

The previous prime is 661717033. The next prime is 661717159. The reversal of 661717141 is 141717166.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 590247025 + 71470116 = 24295^2 + 8454^2 .

It is a cyclic number.

It is not a de Polignac number, because 661717141 - 2¹⁹ = 661192853 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661717097 and 661717106.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661717171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330858570 + 330858571.

It is an arithmetic number, because the mean of its divisors is an integer number (330858571).

Almost surely, 2^661717141 is an apocalyptic number.

It is an amenable number.

661717141 is a deficient number, since it is larger than the sum of its proper divisors (1).

661717141 is an equidigital number, since it uses as much as digits as its factorization.

661717141 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056, while the sum is 34.

The square root of 661717141 is about 25723.8632596272. The cubic root of 661717141 is about 871.4131878921.

The spelling of 661717141 in words is "six hundred sixty-one million, seven hundred seventeen thousand, one hundred forty-one".