20726261 has 2 divisors, whose sum is σ = 20726262. Its totient is φ = 20726260.

The previous prime is 20726257. The next prime is 20726263. The reversal of 20726261 is 16262702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15952036 + 4774225 = 3994^2 + 2185^2 .

It is a cyclic number.

It is not a de Polignac number, because 20726261 - 2² = 20726257 is a prime.

Together with 20726263, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20726261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20726263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10363130 + 10363131.

It is an arithmetic number, because the mean of its divisors is an integer number (10363131).

Almost surely, 2^20726261 is an apocalyptic number.

It is an amenable number.

20726261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20726261 is an equidigital number, since it uses as much as digits as its factorization.

20726261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 20726261 is about 4552.6103501178. The cubic root of 20726261 is about 274.6884007830.

Adding to 20726261 its reverse (16262702), we get a palindrome (36988963).

The spelling of 20726261 in words is "twenty million, seven hundred twenty-six thousand, two hundred sixty-one".