20356721269 has 2 divisors, whose sum is σ = 20356721270. Its totient is φ = 20356721268.

The previous prime is 20356721249. The next prime is 20356721321. The reversal of 20356721269 is 96212765302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20345599044 + 11122225 = 142638^2 + 3335^2 .

It is a cyclic number.

It is not a de Polignac number, because 20356721269 - 2⁹ = 20356720757 is a prime.

It is a super-2 number, since 2×20356721269² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20356721249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10178360634 + 10178360635.

It is an arithmetic number, because the mean of its divisors is an integer number (10178360635).

Almost surely, 2^20356721269 is an apocalyptic number.

It is an amenable number.

20356721269 is a deficient number, since it is larger than the sum of its proper divisors (1).

20356721269 is an equidigital number, since it uses as much as digits as its factorization.

20356721269 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 272160, while the sum is 43.

The spelling of 20356721269 in words is "twenty billion, three hundred fifty-six million, seven hundred twenty-one thousand, two hundred sixty-nine".