661740223 has 2 divisors, whose sum is σ = 661740224. Its totient is φ = 661740222.

The previous prime is 661740221. The next prime is 661740239. The reversal of 661740223 is 322047166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661740223 - 2¹ = 661740221 is a prime.

Together with 661740221, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661740221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330870111 + 330870112.

It is an arithmetic number, because the mean of its divisors is an integer number (330870112).

Almost surely, 2^661740223 is an apocalyptic number.

661740223 is a deficient number, since it is larger than the sum of its proper divisors (1).

661740223 is an equidigital number, since it uses as much as digits as its factorization.

661740223 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 31.

The square root of 661740223 is about 25724.3119052775. The cubic root of 661740223 is about 871.4233199783.

Adding to 661740223 its reverse (322047166), we get a palindrome (983787389).

The spelling of 661740223 in words is "six hundred sixty-one million, seven hundred forty thousand, two hundred twenty-three".