1555605985631 has 2 divisors, whose sum is σ = 1555605985632. Its totient is φ = 1555605985630.

The previous prime is 1555605985627. The next prime is 1555605985639. The reversal of 1555605985631 is 1365895065551.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1555605985631 - 2² = 1555605985627 is a prime.

It is a super-2 number, since 2×1555605985631² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1555605985639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 777802992815 + 777802992816.

It is an arithmetic number, because the mean of its divisors is an integer number (777802992816).

Almost surely, 2^{1555605985631} is an apocalyptic number.

1555605985631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1555605985631 is an equidigital number, since it uses as much as digits as its factorization.

1555605985631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24300000, while the sum is 59.

The spelling of 1555605985631 in words is "one trillion, five hundred fifty-five billion, six hundred five million, nine hundred eighty-five thousand, six hundred thirty-one".