661155223 has 2 divisors, whose sum is σ = 661155224. Its totient is φ = 661155222.

The previous prime is 661155199. The next prime is 661155227. The reversal of 661155223 is 322551166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661155223 - 2¹³ = 661147031 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661155227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330577611 + 330577612.

It is an arithmetic number, because the mean of its divisors is an integer number (330577612).

Almost surely, 2^661155223 is an apocalyptic number.

661155223 is a deficient number, since it is larger than the sum of its proper divisors (1).

661155223 is an equidigital number, since it uses as much as digits as its factorization.

661155223 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10800, while the sum is 31.

The square root of 661155223 is about 25712.9388246462. The cubic root of 661155223 is about 871.1664553660.

The spelling of 661155223 in words is "six hundred sixty-one million, one hundred fifty-five thousand, two hundred twenty-three".