123220421 has 2 divisors, whose sum is σ = 123220422. Its totient is φ = 123220420.

The previous prime is 123220337. The next prime is 123220459. The reversal of 123220421 is 124022321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 112890625 + 10329796 = 10625^2 + 3214^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123220421 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 123220421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123220481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61610210 + 61610211.

It is an arithmetic number, because the mean of its divisors is an integer number (61610211).

Almost surely, 2^123220421 is an apocalyptic number.

It is an amenable number.

123220421 is a deficient number, since it is larger than the sum of its proper divisors (1).

123220421 is an equidigital number, since it uses as much as digits as its factorization.

123220421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 123220421 is about 11100.4694044892. The cubic root of 123220421 is about 497.6158779931.

Adding to 123220421 its reverse (124022321), we get a palindrome (247242742).

The spelling of 123220421 in words is "one hundred twenty-three million, two hundred twenty thousand, four hundred twenty-one".