261421793 has 2 divisors, whose sum is σ = 261421794. Its totient is φ = 261421792.

The previous prime is 261421763. The next prime is 261421813. The reversal of 261421793 is 397124162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198584464 + 62837329 = 14092^2 + 7927^2 .

It is a cyclic number.

It is not a de Polignac number, because 261421793 - 2¹⁰ = 261420769 is a prime.

It is not a weakly prime, because it can be changed into another prime (261421763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130710896 + 130710897.

It is an arithmetic number, because the mean of its divisors is an integer number (130710897).

Almost surely, 2^261421793 is an apocalyptic number.

It is an amenable number.

261421793 is a deficient number, since it is larger than the sum of its proper divisors (1).

261421793 is an equidigital number, since it uses as much as digits as its factorization.

261421793 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 35.

The square root of 261421793 is about 16168.5433171947. The cubic root of 261421793 is about 639.4117258757.

The spelling of 261421793 in words is "two hundred sixty-one million, four hundred twenty-one thousand, seven hundred ninety-three".