20729312309 has 2 divisors, whose sum is σ = 20729312310. Its totient is φ = 20729312308.

The previous prime is 20729312297. The next prime is 20729312381. The reversal of 20729312309 is 90321392702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15648759025 + 5080553284 = 125095^2 + 71278^2 .

It is a cyclic number.

It is not a de Polignac number, because 20729312309 - 2⁸ = 20729312053 is a prime.

It is a super-2 number, since 2×20729312309² (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 (20729312399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10364656154 + 10364656155.

It is an arithmetic number, because the mean of its divisors is an integer number (10364656155).

Almost surely, 2^20729312309 is an apocalyptic number.

It is an amenable number.

20729312309 is a deficient number, since it is larger than the sum of its proper divisors (1).

20729312309 is an equidigital number, since it uses as much as digits as its factorization.

20729312309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 38.

The spelling of 20729312309 in words is "twenty billion, seven hundred twenty-nine million, three hundred twelve thousand, three hundred nine".