21911882521 has 2 divisors, whose sum is σ = 21911882522. Its totient is φ = 21911882520.

The previous prime is 21911882497. The next prime is 21911882537. The reversal of 21911882521 is 12528811912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19144596496 + 2767286025 = 138364^2 + 52605^2 .

It is a cyclic number.

It is not a de Polignac number, because 21911882521 - 2¹³ = 21911874329 is a prime.

It is a super-2 number, since 2×21911882521² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21911882621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10955941260 + 10955941261.

It is an arithmetic number, because the mean of its divisors is an integer number (10955941261).

Almost surely, 2^21911882521 is an apocalyptic number.

It is an amenable number.

21911882521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21911882521 is an equidigital number, since it uses as much as digits as its factorization.

21911882521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23040, while the sum is 40.

The spelling of 21911882521 in words is "twenty-one billion, nine hundred eleven million, eight hundred eighty-two thousand, five hundred twenty-one".