21814624561 has 2 divisors, whose sum is σ = 21814624562. Its totient is φ = 21814624560.

The previous prime is 21814624547. The next prime is 21814624567. The reversal of 21814624561 is 16542641812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21475143936 + 339480625 = 146544^2 + 18425^2 .

It is a cyclic number.

It is not a de Polignac number, because 21814624561 - 2¹⁵ = 21814591793 is a prime.

It is not a weakly prime, because it can be changed into another prime (21814624567) 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, 10907312280 + 10907312281.

It is an arithmetic number, because the mean of its divisors is an integer number (10907312281).

Almost surely, 2^21814624561 is an apocalyptic number.

It is an amenable number.

21814624561 is a deficient number, since it is larger than the sum of its proper divisors (1).

21814624561 is an equidigital number, since it uses as much as digits as its factorization.

21814624561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 92160, while the sum is 40.

The spelling of 21814624561 in words is "twenty-one billion, eight hundred fourteen million, six hundred twenty-four thousand, five hundred sixty-one".