21845737 has 2 divisors, whose sum is σ = 21845738. Its totient is φ = 21845736.

The previous prime is 21845723. The next prime is 21845773. The reversal of 21845737 is 73754812.

Together with next prime (21845773) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13660416 + 8185321 = 3696^2 + 2861^2 .

It is a cyclic number.

It is not a de Polignac number, because 21845737 - 2¹⁹ = 21321449 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21845696 and 21845705.

It is not a weakly prime, because it can be changed into another prime (21845717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10922868 + 10922869.

It is an arithmetic number, because the mean of its divisors is an integer number (10922869).

Almost surely, 2^21845737 is an apocalyptic number.

It is an amenable number.

21845737 is a deficient number, since it is larger than the sum of its proper divisors (1).

21845737 is an equidigital number, since it uses as much as digits as its factorization.

21845737 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47040, while the sum is 37.

The square root of 21845737 is about 4673.9423402520. The cubic root of 21845737 is about 279.5474705571.

It can be divided in two parts, 2184 and 5737, that added together give a square (7921 = 89²).

The spelling of 21845737 in words is "twenty-one million, eight hundred forty-five thousand, seven hundred thirty-seven".