21518647455029 has 2 divisors, whose sum is σ = 21518647455030. Its totient is φ = 21518647455028.

The previous prime is 21518647454977. The next prime is 21518647455037. The reversal of 21518647455029 is 92055474681512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19503661527025 + 2014985928004 = 4416295^2 + 1419502^2 .

It is a cyclic number.

It is not a de Polignac number, because 21518647455029 - 2⁴⁰ = 20419135827253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21518647458029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10759323727514 + 10759323727515.

It is an arithmetic number, because the mean of its divisors is an integer number (10759323727515).

Almost surely, 2^{21518647455029} is an apocalyptic number.

It is an amenable number.

21518647455029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21518647455029 is an equidigital number, since it uses as much as digits as its factorization.

21518647455029 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192000, while the sum is 59.

The spelling of 21518647455029 in words is "twenty-one trillion, five hundred eighteen billion, six hundred forty-seven million, four hundred fifty-five thousand, twenty-nine".