1557481693 has 2 divisors, whose sum is σ = 1557481694. Its totient is φ = 1557481692.

The previous prime is 1557481669. The next prime is 1557481721. The reversal of 1557481693 is 3961847551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 854860644 + 702621049 = 29238^2 + 26507^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1557481693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1557481493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 778740846 + 778740847.

It is an arithmetic number, because the mean of its divisors is an integer number (778740847).

Almost surely, 2^1557481693 is an apocalyptic number.

It is an amenable number.

1557481693 is a deficient number, since it is larger than the sum of its proper divisors (1).

1557481693 is an equidigital number, since it uses as much as digits as its factorization.

1557481693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 907200, while the sum is 49.

The square root of 1557481693 is about 39464.9425819929. The cubic root of 1557481693 is about 1159.1535871193.

The spelling of 1557481693 in words is "one billion, five hundred fifty-seven million, four hundred eighty-one thousand, six hundred ninety-three".