54856025816821 has 2 divisors, whose sum is σ = 54856025816822. Its totient is φ = 54856025816820.

The previous prime is 54856025816819. The next prime is 54856025816927. The reversal of 54856025816821 is 12861852065845.

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., 27452999472721 + 27403026344100 = 5239561^2 + 5234790^2 .

It is a cyclic number.

It is not a de Polignac number, because 54856025816821 - 2¹ = 54856025816819 is a prime.

Together with 54856025816819, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 54856025816821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (54856023816821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27428012908410 + 27428012908411.

It is an arithmetic number, because the mean of its divisors is an integer number (27428012908411).

Almost surely, 2^{54856025816821} is an apocalyptic number.

It is an amenable number.

54856025816821 is a deficient number, since it is larger than the sum of its proper divisors (1).

54856025816821 is an equidigital number, since it uses as much as digits as its factorization.

54856025816821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36864000, while the sum is 61.

The spelling of 54856025816821 in words is "fifty-four trillion, eight hundred fifty-six billion, twenty-five million, eight hundred sixteen thousand, eight hundred twenty-one".