21712157067121 has 2 divisors, whose sum is σ = 21712157067122. Its totient is φ = 21712157067120.

The previous prime is 21712157067119. The next prime is 21712157067163. The reversal of 21712157067121 is 12176075121712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10911863562721 + 10800293504400 = 3303311^2 + 3286380^2 .

It is a cyclic number.

It is not a de Polignac number, because 21712157067121 - 2¹ = 21712157067119 is a prime.

Together with 21712157067119, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21712157067421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10856078533560 + 10856078533561.

It is an arithmetic number, because the mean of its divisors is an integer number (10856078533561).

Almost surely, 2^{21712157067121} is an apocalyptic number.

It is an amenable number.

21712157067121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21712157067121 is an equidigital number, since it uses as much as digits as its factorization.

21712157067121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82320, while the sum is 43.

The spelling of 21712157067121 in words is "twenty-one trillion, seven hundred twelve billion, one hundred fifty-seven million, sixty-seven thousand, one hundred twenty-one".