54391706521 has 2 divisors, whose sum is σ = 54391706522. Its totient is φ = 54391706520.

The previous prime is 54391706519. The next prime is 54391706539. The reversal of 54391706521 is 12560719345.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30279828121 + 24111878400 = 174011^2 + 155280^2 .

It is a cyclic number.

It is not a de Polignac number, because 54391706521 - 2¹ = 54391706519 is a prime.

Together with 54391706519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (54391706321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27195853260 + 27195853261.

It is an arithmetic number, because the mean of its divisors is an integer number (27195853261).

Almost surely, 2^54391706521 is an apocalyptic number.

It is an amenable number.

54391706521 is a deficient number, since it is larger than the sum of its proper divisors (1).

54391706521 is an equidigital number, since it uses as much as digits as its factorization.

54391706521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 226800, while the sum is 43.

The spelling of 54391706521 in words is "fifty-four billion, three hundred ninety-one million, seven hundred six thousand, five hundred twenty-one".