21760549 has 2 divisors, whose sum is σ = 21760550. Its totient is φ = 21760548.

The previous prime is 21760547. The next prime is 21760559. The reversal of 21760549 is 94506712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21687649 + 72900 = 4657^2 + 270^2 .

It is a cyclic number.

It is not a de Polignac number, because 21760549 - 2¹ = 21760547 is a prime.

Together with 21760547, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21760547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10880274 + 10880275.

It is an arithmetic number, because the mean of its divisors is an integer number (10880275).

Almost surely, 2^21760549 is an apocalyptic number.

It is an amenable number.

21760549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21760549 is an equidigital number, since it uses as much as digits as its factorization.

21760549 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 21760549 is about 4664.8203609571. The cubic root of 21760549 is about 279.1836297507.

The spelling of 21760549 in words is "twenty-one million, seven hundred sixty thousand, five hundred forty-nine".