661320223 has 2 divisors, whose sum is σ = 661320224. Its totient is φ = 661320222.

The previous prime is 661320211. The next prime is 661320229. The reversal of 661320223 is 322023166.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661320223 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661320229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330660111 + 330660112.

It is an arithmetic number, because the mean of its divisors is an integer number (330660112).

Almost surely, 2^661320223 is an apocalyptic number.

661320223 is a deficient number, since it is larger than the sum of its proper divisors (1).

661320223 is an equidigital number, since it uses as much as digits as its factorization.

661320223 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 25.

The square root of 661320223 is about 25716.1471258818. The cubic root of 661320223 is about 871.2389196952.

Adding to 661320223 its reverse (322023166), we get a palindrome (983343389).

The spelling of 661320223 in words is "six hundred sixty-one million, three hundred twenty thousand, two hundred twenty-three".