5655868721 has 4 divisors (see below), whose sum is σ = 5656028772. Its totient is φ = 5655708672.

The previous prime is 5655868709. The next prime is 5655868727. The reversal of 5655868721 is 1278685565.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1278685565 = 5 ⋅255737113.

It can be written as a sum of positive squares in 2 ways, for example, as 3923644321 + 1732224400 = 62639^2 + 41620^2 .

It is a cyclic number.

It is not a de Polignac number, because 5655868721 - 2¹⁴ = 5655852337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5655868727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1016 + ... + 106361.

It is an arithmetic number, because the mean of its divisors is an integer number (1414007193).

Almost surely, 2^5655868721 is an apocalyptic number.

It is an amenable number.

5655868721 is a deficient number, since it is larger than the sum of its proper divisors (160051).

5655868721 is a wasteful number, since it uses less digits than its factorization.

5655868721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160050.

The product of its digits is 4032000, while the sum is 53.

The square root of 5655868721 is about 75205.5099111761. The cubic root of 5655868721 is about 1781.6939562633.

The spelling of 5655868721 in words is "five billion, six hundred fifty-five million, eight hundred sixty-eight thousand, seven hundred twenty-one".