423636721 has 2 divisors, whose sum is σ = 423636722. Its totient is φ = 423636720.

The previous prime is 423636679. The next prime is 423636751. The reversal of 423636721 is 127636324.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 404452321 + 19184400 = 20111^2 + 4380^2 .

It is a cyclic number.

It is not a de Polignac number, because 423636721 - 2¹⁹ = 423112433 is a prime.

It is not a weakly prime, because it can be changed into another prime (423636751) 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, 211818360 + 211818361.

It is an arithmetic number, because the mean of its divisors is an integer number (211818361).

Almost surely, 2^423636721 is an apocalyptic number.

It is an amenable number.

423636721 is a deficient number, since it is larger than the sum of its proper divisors (1).

423636721 is an equidigital number, since it uses as much as digits as its factorization.

423636721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 34.

The square root of 423636721 is about 20582.4371977664. The cubic root of 423636721 is about 751.0425329767.

The spelling of 423636721 in words is "four hundred twenty-three million, six hundred thirty-six thousand, seven hundred twenty-one".