21522650561 has 2 divisors, whose sum is σ = 21522650562. Its totient is φ = 21522650560.

The previous prime is 21522650537. The next prime is 21522650587. The reversal of 21522650561 is 16505622512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15241137025 + 6281513536 = 123455^2 + 79256^2 .

It is a cyclic number.

It is not a de Polignac number, because 21522650561 - 2³⁰ = 20448908737 is a prime.

It is a super-2 number, since 2×21522650561² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21522650521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10761325280 + 10761325281.

It is an arithmetic number, because the mean of its divisors is an integer number (10761325281).

Almost surely, 2^21522650561 is an apocalyptic number.

It is an amenable number.

21522650561 is a deficient number, since it is larger than the sum of its proper divisors (1).

21522650561 is an equidigital number, since it uses as much as digits as its factorization.

21522650561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36000, while the sum is 35.

The spelling of 21522650561 in words is "twenty-one billion, five hundred twenty-two million, six hundred fifty thousand, five hundred sixty-one".