21213600655487 has 2 divisors, whose sum is σ = 21213600655488. Its totient is φ = 21213600655486.

The previous prime is 21213600655477. The next prime is 21213600655531. The reversal of 21213600655487 is 78455600631212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21213600655487 - 2³⁰ = 21212526913663 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213600655447) 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, 10606800327743 + 10606800327744.

It is an arithmetic number, because the mean of its divisors is an integer number (10606800327744).

Almost surely, 2^{21213600655487} is an apocalyptic number.

21213600655487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213600655487 is an equidigital number, since it uses as much as digits as its factorization.

21213600655487 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2419200, while the sum is 50.

The spelling of 21213600655487 in words is "twenty-one trillion, two hundred thirteen billion, six hundred million, six hundred fifty-five thousand, four hundred eighty-seven".