13820561 has 2 divisors, whose sum is σ = 13820562. Its totient is φ = 13820560.

The previous prime is 13820551. The next prime is 13820563. The reversal of 13820561 is 16502831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7595536 + 6225025 = 2756^2 + 2495^2 .

It is a cyclic number.

It is not a de Polignac number, because 13820561 - 2¹⁸ = 13558417 is a prime.

Together with 13820563, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 13820561.

It is not a weakly prime, because it can be changed into another prime (13820563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6910280 + 6910281.

It is an arithmetic number, because the mean of its divisors is an integer number (6910281).

Almost surely, 2^13820561 is an apocalyptic number.

It is an amenable number.

13820561 is a deficient number, since it is larger than the sum of its proper divisors (1).

13820561 is an equidigital number, since it uses as much as digits as its factorization.

13820561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 13820561 is about 3717.6015117277. The cubic root of 13820561 is about 239.9800967291.

The spelling of 13820561 in words is "thirteen million, eight hundred twenty thousand, five hundred sixty-one".