21845429657 has 2 divisors, whose sum is σ = 21845429658. Its totient is φ = 21845429656.

The previous prime is 21845429651. The next prime is 21845429701. The reversal of 21845429657 is 75692454812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21126331801 + 719097856 = 145349^2 + 26816^2 .

It is a cyclic number.

It is not a de Polignac number, because 21845429657 - 2³² = 17550462361 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21845429599 and 21845429608.

It is not a weakly prime, because it can be changed into another prime (21845429651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10922714828 + 10922714829.

It is an arithmetic number, because the mean of its divisors is an integer number (10922714829).

Almost surely, 2^21845429657 is an apocalyptic number.

It is an amenable number.

21845429657 is a deficient number, since it is larger than the sum of its proper divisors (1).

21845429657 is an equidigital number, since it uses as much as digits as its factorization.

21845429657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4838400, while the sum is 53.

The spelling of 21845429657 in words is "twenty-one billion, eight hundred forty-five million, four hundred twenty-nine thousand, six hundred fifty-seven".