12720322557 has 6 divisors (see below), whose sum is σ = 18373799262. Its totient is φ = 8480215032.

The previous prime is 12720322543. The next prime is 12720322609. The reversal of 12720322557 is 75522302721.

12720322557 is a `hidden beast` number, since 1 + 2 + 72 + 0 + 32 + 2 + 557 = 666.

It can be written as a sum of positive squares in only one way, i.e., 8365114521 + 4355208036 = 91461^2 + 65994^2 .

It is not a de Polignac number, because 12720322557 - 2¹⁴ = 12720306173 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12720322507) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 706684578 + ... + 706684595.

It is an arithmetic number, because the mean of its divisors is an integer number (3062299877).

Almost surely, 2^12720322557 is an apocalyptic number.

It is an amenable number.

12720322557 is a deficient number, since it is larger than the sum of its proper divisors (5653476705).

12720322557 is a wasteful number, since it uses less digits than its factorization.

12720322557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1413369179 (or 1413369176 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 36.

The spelling of 12720322557 in words is "twelve billion, seven hundred twenty million, three hundred twenty-two thousand, five hundred fifty-seven".