55550772581 has 4 divisors (see below), whose sum is σ = 55592825964. Its totient is φ = 55508719200.

The previous prime is 55550772521. The next prime is 55550772637. The reversal of 55550772581 is 18527705555.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18527705555 = 5 ⋅3705541111.

It can be written as a sum of positive squares in 2 ways, for example, as 32601552481 + 22949220100 = 180559^2 + 151490^2 .

It is a cyclic number.

It is not a de Polignac number, because 55550772581 - 2¹⁸ = 55550510437 is a prime.

It is a super-2 number, since 2×55550772581² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55550772521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21024710 + ... + 21027351.

It is an arithmetic number, because the mean of its divisors is an integer number (13898206491).

Almost surely, 2^55550772581 is an apocalyptic number.

It is an amenable number.

55550772581 is a deficient number, since it is larger than the sum of its proper divisors (42053383).

55550772581 is a wasteful number, since it uses less digits than its factorization.

55550772581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42053382.

The product of its (nonzero) digits is 2450000, while the sum is 50.

The spelling of 55550772581 in words is "fifty-five billion, five hundred fifty million, seven hundred seventy-two thousand, five hundred eighty-one".