661026617 has 2 divisors, whose sum is σ = 661026618. Its totient is φ = 661026616.

The previous prime is 661026557. The next prime is 661026629. The reversal of 661026617 is 716620166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 382437136 + 278589481 = 19556^2 + 16691^2 .

It is a cyclic number.

It is not a de Polignac number, because 661026617 - 2²² = 656832313 is a prime.

It is not a weakly prime, because it can be changed into another prime (661026637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330513308 + 330513309.

It is an arithmetic number, because the mean of its divisors is an integer number (330513309).

Almost surely, 2^661026617 is an apocalyptic number.

It is an amenable number.

661026617 is a deficient number, since it is larger than the sum of its proper divisors (1).

661026617 is an equidigital number, since it uses as much as digits as its factorization.

661026617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 661026617 is about 25710.4378998103. The cubic root of 661026617 is about 871.1099661108.

The spelling of 661026617 in words is "six hundred sixty-one million, twenty-six thousand, six hundred seventeen".