55743871721 has 2 divisors, whose sum is σ = 55743871722. Its totient is φ = 55743871720.

The previous prime is 55743871697. The next prime is 55743871747. The reversal of 55743871721 is 12717834755.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34312375696 + 21431496025 = 185236^2 + 146395^2 .

It is a cyclic number.

It is not a de Polignac number, because 55743871721 - 2²⁶ = 55676762857 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 55743871721.

It is not a weakly prime, because it can be changed into another prime (55743271721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27871935860 + 27871935861.

It is an arithmetic number, because the mean of its divisors is an integer number (27871935861).

Almost surely, 2^55743871721 is an apocalyptic number.

It is an amenable number.

55743871721 is a deficient number, since it is larger than the sum of its proper divisors (1).

55743871721 is an equidigital number, since it uses as much as digits as its factorization.

55743871721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1646400, while the sum is 50.

The spelling of 55743871721 in words is "fifty-five billion, seven hundred forty-three million, eight hundred seventy-one thousand, seven hundred twenty-one".