636145261 has 2 divisors, whose sum is σ = 636145262. Its totient is φ = 636145260.

The previous prime is 636145249. The next prime is 636145267. The reversal of 636145261 is 162541636.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 420496036 + 215649225 = 20506^2 + 14685^2 .

It is a cyclic number.

It is not a de Polignac number, because 636145261 - 2⁹ = 636144749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636145267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318072630 + 318072631.

It is an arithmetic number, because the mean of its divisors is an integer number (318072631).

Almost surely, 2^636145261 is an apocalyptic number.

It is an amenable number.

636145261 is a deficient number, since it is larger than the sum of its proper divisors (1).

636145261 is an equidigital number, since it uses as much as digits as its factorization.

636145261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25920, while the sum is 34.

The square root of 636145261 is about 25221.9202480699. The cubic root of 636145261 is about 860.0402275216.

Adding to 636145261 its reverse (162541636), we get a palindrome (798686897).

The spelling of 636145261 in words is "six hundred thirty-six million, one hundred forty-five thousand, two hundred sixty-one".