20261281 has 2 divisors, whose sum is σ = 20261282. Its totient is φ = 20261280.

The previous prime is 20261279. The next prime is 20261287. The reversal of 20261281 is 18216202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15872256 + 4389025 = 3984^2 + 2095^2 .

It is a cyclic number.

It is not a de Polignac number, because 20261281 - 2¹ = 20261279 is a prime.

It is a super-2 number, since 2×20261281² = 821039015521922, which contains 22 as substring.

Together with 20261279, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20261287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10130640 + 10130641.

It is an arithmetic number, because the mean of its divisors is an integer number (10130641).

Almost surely, 2^20261281 is an apocalyptic number.

It is an amenable number.

20261281 is a deficient number, since it is larger than the sum of its proper divisors (1).

20261281 is an equidigital number, since it uses as much as digits as its factorization.

20261281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 20261281 is about 4501.2532699238. The cubic root of 20261281 is about 272.6186941891.

Adding to 20261281 its reverse (18216202), we get a palindrome (38477483).

The spelling of 20261281 in words is "twenty million, two hundred sixty-one thousand, two hundred eighty-one".