21112320709 has 2 divisors, whose sum is σ = 21112320710. Its totient is φ = 21112320708.

The previous prime is 21112320679. The next prime is 21112320721. The reversal of 21112320709 is 90702321112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21111218209 + 1102500 = 145297^2 + 1050^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112320709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112320739) 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, 10556160354 + 10556160355.

It is an arithmetic number, because the mean of its divisors is an integer number (10556160355).

Almost surely, 2^21112320709 is an apocalyptic number.

It is an amenable number.

21112320709 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112320709 is an equidigital number, since it uses as much as digits as its factorization.

21112320709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 28.

The spelling of 21112320709 in words is "twenty-one billion, one hundred twelve million, three hundred twenty thousand, seven hundred nine".