591663421 has 2 divisors, whose sum is σ = 591663422. Its totient is φ = 591663420.

The previous prime is 591663419. The next prime is 591663437. The reversal of 591663421 is 124366195.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 384591321 + 207072100 = 19611^2 + 14390^2 .

It is a cyclic number.

It is not a de Polignac number, because 591663421 - 2¹ = 591663419 is a prime.

Together with 591663419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (591663491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 295831710 + 295831711.

It is an arithmetic number, because the mean of its divisors is an integer number (295831711).

Almost surely, 2^591663421 is an apocalyptic number.

It is an amenable number.

591663421 is a deficient number, since it is larger than the sum of its proper divisors (1).

591663421 is an equidigital number, since it uses as much as digits as its factorization.

591663421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 37.

The square root of 591663421 is about 24324.1324819612. The cubic root of 591663421 is about 839.5081308778.

The spelling of 591663421 in words is "five hundred ninety-one million, six hundred sixty-three thousand, four hundred twenty-one".