1555605985231 has 2 divisors, whose sum is σ = 1555605985232. Its totient is φ = 1555605985230.

The previous prime is 1555605985229. The next prime is 1555605985301. The reversal of 1555605985231 is 1325895065551.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1555605985231 - 2¹ = 1555605985229 is a prime.

It is a super-2 number, since 2×1555605985231² (a number of 25 digits) contains 22 as substring.

Together with 1555605985229, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1555605985631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 777802992615 + 777802992616.

It is an arithmetic number, because the mean of its divisors is an integer number (777802992616).

Almost surely, 2^{1555605985231} is an apocalyptic number.

1555605985231 is a deficient number, since it is larger than the sum of its proper divisors (1).

1555605985231 is an equidigital number, since it uses as much as digits as its factorization.

1555605985231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8100000, while the sum is 55.

It can be divided in two parts, 1555605 and 985231, that added together give a square (2540836 = 1594²).

The spelling of 1555605985231 in words is "one trillion, five hundred fifty-five billion, six hundred five million, nine hundred eighty-five thousand, two hundred thirty-one".