21745719635309 has 2 divisors, whose sum is σ = 21745719635310. Its totient is φ = 21745719635308.

The previous prime is 21745719635291. The next prime is 21745719635371. The reversal of 21745719635309 is 90353691754712.

It is a happy number.

It is an a-pointer prime, because the next prime (21745719635371) can be obtained adding 21745719635309 to its sum of digits (62).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21280045780900 + 465673854409 = 4613030^2 + 682403^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21745719635309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21745719635389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10872859817654 + 10872859817655.

It is an arithmetic number, because the mean of its divisors is an integer number (10872859817655).

Almost surely, 2^{21745719635309} is an apocalyptic number.

It is an amenable number.

21745719635309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21745719635309 is an equidigital number, since it uses as much as digits as its factorization.

21745719635309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 42865200, while the sum is 62.

The spelling of 21745719635309 in words is "twenty-one trillion, seven hundred forty-five billion, seven hundred nineteen million, six hundred thirty-five thousand, three hundred nine".