421043993 has 2 divisors, whose sum is σ = 421043994. Its totient is φ = 421043992.

The previous prime is 421043939. The next prime is 421043999. The reversal of 421043993 is 399340124.

Together with previous prime (421043939) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 420537049 + 506944 = 20507^2 + 712^2 .

It is a cyclic number.

It is not a de Polignac number, because 421043993 - 2⁸ = 421043737 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (421043999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210521996 + 210521997.

It is an arithmetic number, because the mean of its divisors is an integer number (210521997).

Almost surely, 2^421043993 is an apocalyptic number.

It is an amenable number.

421043993 is a deficient number, since it is larger than the sum of its proper divisors (1).

421043993 is an equidigital number, since it uses as much as digits as its factorization.

421043993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 35.

The square root of 421043993 is about 20519.3565444923. The cubic root of 421043993 is about 749.5072277123.

The spelling of 421043993 in words is "four hundred twenty-one million, forty-three thousand, nine hundred ninety-three".