791566421 has 2 divisors, whose sum is σ = 791566422. Its totient is φ = 791566420.

The previous prime is 791566379. The next prime is 791566423. The reversal of 791566421 is 124665197.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 738480625 + 53085796 = 27175^2 + 7286^2 .

It is a cyclic number.

It is not a de Polignac number, because 791566421 - 2¹⁸ = 791304277 is a prime.

Together with 791566423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (791566423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 395783210 + 395783211.

It is an arithmetic number, because the mean of its divisors is an integer number (395783211).

Almost surely, 2^791566421 is an apocalyptic number.

It is an amenable number.

791566421 is a deficient number, since it is larger than the sum of its proper divisors (1).

791566421 is an equidigital number, since it uses as much as digits as its factorization.

791566421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 41.

The square root of 791566421 is about 28134.7902249155. The cubic root of 791566421 is about 925.0441356102.

The spelling of 791566421 in words is "seven hundred ninety-one million, five hundred sixty-six thousand, four hundred twenty-one".