21720355038527 has 2 divisors, whose sum is σ = 21720355038528. Its totient is φ = 21720355038526.

The previous prime is 21720355038523. The next prime is 21720355038617. The reversal of 21720355038527 is 72583055302712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21720355038527 - 2² = 21720355038523 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21720355038523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10860177519263 + 10860177519264.

It is an arithmetic number, because the mean of its divisors is an integer number (10860177519264).

Almost surely, 2^{21720355038527} is an apocalyptic number.

21720355038527 is a deficient number, since it is larger than the sum of its proper divisors (1).

21720355038527 is an equidigital number, since it uses as much as digits as its factorization.

21720355038527 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3528000, while the sum is 50.

The spelling of 21720355038527 in words is "twenty-one trillion, seven hundred twenty billion, three hundred fifty-five million, thirty-eight thousand, five hundred twenty-seven".