1555555555538 has 4 divisors (see below), whose sum is σ = 2333333333310. Its totient is φ = 777777777768.

The previous prime is 1555555555529. The next prime is 1555555555559. The reversal of 1555555555538 is 8355555555551.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1263639029689 + 291916525849 = 1124117^2 + 540293^2 .

It is a Curzon number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 388888888883 + ... + 388888888886.

Almost surely, 2^{1555555555538} is an apocalyptic number.

1555555555538 is a deficient number, since it is larger than the sum of its proper divisors (777777777772).

1555555555538 is an equidigital number, since it uses as much as digits as its factorization.

1555555555538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 777777777771.

The product of its digits is 234375000, while the sum is 62.

The spelling of 1555555555538 in words is "one trillion, five hundred fifty-five billion, five hundred fifty-five million, five hundred fifty-five thousand, five hundred thirty-eight".