720431993 has 2 divisors, whose sum is σ = 720431994. Its totient is φ = 720431992.

The previous prime is 720431941. The next prime is 720432043. The reversal of 720431993 is 399134027.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 370293049 + 350138944 = 19243^2 + 18712^2 .

It is an emirp because it is prime and its reverse (399134027) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 720431993 - 2¹⁶ = 720366457 is a prime.

It is not a weakly prime, because it can be changed into another prime (720431923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360215996 + 360215997.

It is an arithmetic number, because the mean of its divisors is an integer number (360215997).

Almost surely, 2^720431993 is an apocalyptic number.

It is an amenable number.

720431993 is a deficient number, since it is larger than the sum of its proper divisors (1).

720431993 is an equidigital number, since it uses as much as digits as its factorization.

720431993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40824, while the sum is 38.

The square root of 720431993 is about 26840.8642372037. The cubic root of 720431993 is about 896.4601667585.

The spelling of 720431993 in words is "seven hundred twenty million, four hundred thirty-one thousand, nine hundred ninety-three".