654534213565621 has 2 divisors, whose sum is σ = 654534213565622. Its totient is φ = 654534213565620.

The previous prime is 654534213565619. The next prime is 654534213565663. The reversal of 654534213565621 is 126565312435456.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 438658927202596 + 215875286363025 = 20944186^2 + 14692695^2 .

It is a cyclic number.

It is not a de Polignac number, because 654534213565621 - 2¹ = 654534213565619 is a prime.

Together with 654534213565619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (654534213565321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 327267106782810 + 327267106782811.

It is an arithmetic number, because the mean of its divisors is an integer number (327267106782811).

Almost surely, 2^{654534213565621} is an apocalyptic number.

It is an amenable number.

654534213565621 is a deficient number, since it is larger than the sum of its proper divisors (1).

654534213565621 is an equidigital number, since it uses as much as digits as its factorization.

654534213565621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760000, while the sum is 58.

The spelling of 654534213565621 in words is "six hundred fifty-four trillion, five hundred thirty-four billion, two hundred thirteen million, five hundred sixty-five thousand, six hundred twenty-one".