20356721039 has 2 divisors, whose sum is σ = 20356721040. Its totient is φ = 20356721038.

The previous prime is 20356720999. The next prime is 20356721041. The reversal of 20356721039 is 93012765302.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20356721039 is a prime.

Together with 20356721041, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20356720993 and 20356721011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20356721059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10178360519 + 10178360520.

It is an arithmetic number, because the mean of its divisors is an integer number (10178360520).

Almost surely, 2^20356721039 is an apocalyptic number.

20356721039 is a deficient number, since it is larger than the sum of its proper divisors (1).

20356721039 is an equidigital number, since it uses as much as digits as its factorization.

20356721039 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 68040, while the sum is 38.

The spelling of 20356721039 in words is "twenty billion, three hundred fifty-six million, seven hundred twenty-one thousand, thirty-nine".