21404621554529 has 2 divisors, whose sum is σ = 21404621554530. Its totient is φ = 21404621554528.

The previous prime is 21404621554493. The next prime is 21404621554543. The reversal of 21404621554529 is 92545512640412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17918458320400 + 3486163234129 = 4233020^2 + 1867127^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21404621554529 is a prime.

It is a super-3 number, since 3×21404621554529³ (a number of 41 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21404621554579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10702310777264 + 10702310777265.

It is an arithmetic number, because the mean of its divisors is an integer number (10702310777265).

Almost surely, 2^{21404621554529} is an apocalyptic number.

It is an amenable number.

21404621554529 is a deficient number, since it is larger than the sum of its proper divisors (1).

21404621554529 is an equidigital number, since it uses as much as digits as its factorization.

21404621554529 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456000, while the sum is 50.

The spelling of 21404621554529 in words is "twenty-one trillion, four hundred four billion, six hundred twenty-one million, five hundred fifty-four thousand, five hundred twenty-nine".