661335533189 has 2 divisors, whose sum is σ = 661335533190. Its totient is φ = 661335533188.

The previous prime is 661335533161. The next prime is 661335533239. The reversal of 661335533189 is 981335533166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 649582805089 + 11752728100 = 805967^2 + 108410^2 .

It is a cyclic number.

It is not a de Polignac number, because 661335533189 - 2³² = 657040565893 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661335533189.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661335553189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330667766594 + 330667766595.

It is an arithmetic number, because the mean of its divisors is an integer number (330667766595).

Almost surely, 2^661335533189 is an apocalyptic number.

It is an amenable number.

661335533189 is a deficient number, since it is larger than the sum of its proper divisors (1).

661335533189 is an equidigital number, since it uses as much as digits as its factorization.

661335533189 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5248800, while the sum is 53.

The spelling of 661335533189 in words is "six hundred sixty-one billion, three hundred thirty-five million, five hundred thirty-three thousand, one hundred eighty-nine".