21709822481 has 2 divisors, whose sum is σ = 21709822482. Its totient is φ = 21709822480.

The previous prime is 21709822439. The next prime is 21709822493. The reversal of 21709822481 is 18422890712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21273681025 + 436141456 = 145855^2 + 20884^2 .

It is a cyclic number.

It is not a de Polignac number, because 21709822481 - 2³⁰ = 20636080657 is a prime.

It is a super-2 number, since 2×21709822481² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21709822411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10854911240 + 10854911241.

It is an arithmetic number, because the mean of its divisors is an integer number (10854911241).

Almost surely, 2^21709822481 is an apocalyptic number.

It is an amenable number.

21709822481 is a deficient number, since it is larger than the sum of its proper divisors (1).

21709822481 is an equidigital number, since it uses as much as digits as its factorization.

21709822481 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 129024, while the sum is 44.

The spelling of 21709822481 in words is "twenty-one billion, seven hundred nine million, eight hundred twenty-two thousand, four hundred eighty-one".