1581612636557 has 2 divisors, whose sum is σ = 1581612636558. Its totient is φ = 1581612636556.

The previous prime is 1581612636553. The next prime is 1581612636563. The reversal of 1581612636557 is 7556362161851.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1579933358116 + 1679278441 = 1256954^2 + 40979^2 .

It is a cyclic number.

It is not a de Polignac number, because 1581612636557 - 2² = 1581612636553 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1581612636551) 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, 790806318278 + 790806318279.

It is an arithmetic number, because the mean of its divisors is an integer number (790806318279).

Almost surely, 2^{1581612636557} is an apocalyptic number.

It is an amenable number.

1581612636557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1581612636557 is an equidigital number, since it uses as much as digits as its factorization.

1581612636557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072000, while the sum is 56.

The spelling of 1581612636557 in words is "one trillion, five hundred eighty-one billion, six hundred twelve million, six hundred thirty-six thousand, five hundred fifty-seven".