665561636323 has 2 divisors, whose sum is σ = 665561636324. Its totient is φ = 665561636322.

The previous prime is 665561636237. The next prime is 665561636339. The reversal of 665561636323 is 323636165566.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 665561636323 - 2²¹ = 665559539171 is a prime.

It is not a weakly prime, because it can be changed into another prime (665561636423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332780818161 + 332780818162.

It is an arithmetic number, because the mean of its divisors is an integer number (332780818162).

Almost surely, 2^665561636323 is an apocalyptic number.

665561636323 is a deficient number, since it is larger than the sum of its proper divisors (1).

665561636323 is an equidigital number, since it uses as much as digits as its factorization.

665561636323 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10497600, while the sum is 52.

The spelling of 665561636323 in words is "six hundred sixty-five billion, five hundred sixty-one million, six hundred thirty-six thousand, three hundred twenty-three".