20635261 has 2 divisors, whose sum is σ = 20635262. Its totient is φ = 20635260.

The previous prime is 20635231. The next prime is 20635291. The reversal of 20635261 is 16253602.

It is a balanced prime because it is at equal distance from previous prime (20635231) and next prime (20635291).

It can be written as a sum of positive squares in only one way, i.e., 13176900 + 7458361 = 3630^2 + 2731^2 .

It is a cyclic number.

It is not a de Polignac number, because 20635261 - 2¹⁵ = 20602493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20635201) 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, 10317630 + 10317631.

It is an arithmetic number, because the mean of its divisors is an integer number (10317631).

Almost surely, 2^20635261 is an apocalyptic number.

It is an amenable number.

20635261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20635261 is an equidigital number, since it uses as much as digits as its factorization.

20635261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 20635261 is about 4542.6050895934. The cubic root of 20635261 is about 274.2857985465.

Adding to 20635261 its reverse (16253602), we get a palindrome (36888863).

It can be divided in two parts, 206 and 35261, that multiplied together give a triangular number (7263766 = T₃₈₁₁).

The spelling of 20635261 in words is "twenty million, six hundred thirty-five thousand, two hundred sixty-one".