661765583 has 2 divisors, whose sum is σ = 661765584. Its totient is φ = 661765582.

The previous prime is 661765561. The next prime is 661765607. The reversal of 661765583 is 385567166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661765583 - 2¹² = 661761487 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661765183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330882791 + 330882792.

It is an arithmetic number, because the mean of its divisors is an integer number (330882792).

Almost surely, 2^661765583 is an apocalyptic number.

661765583 is a deficient number, since it is larger than the sum of its proper divisors (1).

661765583 is an equidigital number, since it uses as much as digits as its factorization.

661765583 is an evil number, because the sum of its binary digits is even.

The product of its digits is 907200, while the sum is 47.

The square root of 661765583 is about 25724.8048194734. The cubic root of 661765583 is about 871.4344517449.

The spelling of 661765583 in words is "six hundred sixty-one million, seven hundred sixty-five thousand, five hundred eighty-three".