21554610630617 has 2 divisors, whose sum is σ = 21554610630618. Its totient is φ = 21554610630616.

The previous prime is 21554610630559. The next prime is 21554610630697. The reversal of 21554610630617 is 71603601645512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15517840254361 + 6036770376256 = 3939269^2 + 2456984^2 .

It is a cyclic number.

It is not a de Polignac number, because 21554610630617 - 2⁸ = 21554610630361 is a prime.

It is not a weakly prime, because it can be changed into another prime (21554610630697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10777305315308 + 10777305315309.

It is an arithmetic number, because the mean of its divisors is an integer number (10777305315309).

Almost surely, 2^{21554610630617} is an apocalyptic number.

It is an amenable number.

21554610630617 is a deficient number, since it is larger than the sum of its proper divisors (1).

21554610630617 is an equidigital number, since it uses as much as digits as its factorization.

21554610630617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 907200, while the sum is 47.

The spelling of 21554610630617 in words is "twenty-one trillion, five hundred fifty-four billion, six hundred ten million, six hundred thirty thousand, six hundred seventeen".