721421423 has 2 divisors, whose sum is σ = 721421424. Its totient is φ = 721421422.

The previous prime is 721421417. The next prime is 721421447. The reversal of 721421423 is 324124127.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 721421423 - 2¹⁴ = 721405039 is a prime.

It is a Sophie Germain prime.

It is equal to p_37303811 and since 721421423 and 37303811 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 721421392 and 721421401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721424423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360710711 + 360710712.

It is an arithmetic number, because the mean of its divisors is an integer number (360710712).

Almost surely, 2^721421423 is an apocalyptic number.

721421423 is a deficient number, since it is larger than the sum of its proper divisors (1).

721421423 is an equidigital number, since it uses as much as digits as its factorization.

721421423 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 26.

The square root of 721421423 is about 26859.2893241798. The cubic root of 721421423 is about 896.8703738029.

The spelling of 721421423 in words is "seven hundred twenty-one million, four hundred twenty-one thousand, four hundred twenty-three".