20721767207 has 2 divisors, whose sum is σ = 20721767208. Its totient is φ = 20721767206.

The previous prime is 20721767197. The next prime is 20721767219. The reversal of 20721767207 is 70276712702.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20721767207 is a prime.

It is a super-2 number, since 2×20721767207² (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 (20721767257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10360883603 + 10360883604.

It is an arithmetic number, because the mean of its divisors is an integer number (10360883604).

Almost surely, 2^20721767207 is an apocalyptic number.

20721767207 is a deficient number, since it is larger than the sum of its proper divisors (1).

20721767207 is an equidigital number, since it uses as much as digits as its factorization.

20721767207 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 115248, while the sum is 41.

The spelling of 20721767207 in words is "twenty billion, seven hundred twenty-one million, seven hundred sixty-seven thousand, two hundred seven".