1557481649 has 2 divisors, whose sum is σ = 1557481650. Its totient is φ = 1557481648.

The previous prime is 1557481609. The next prime is 1557481669. The reversal of 1557481649 is 9461847551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1547871649 + 9610000 = 39343^2 + 3100^2 .

It is a cyclic number.

It is not a de Polignac number, because 1557481649 - 2¹² = 1557477553 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1557481597 and 1557481606.

It is not a weakly prime, because it can be changed into another prime (1557481609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 778740824 + 778740825.

It is an arithmetic number, because the mean of its divisors is an integer number (778740825).

Almost surely, 2^1557481649 is an apocalyptic number.

It is an amenable number.

1557481649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1557481649 is an equidigital number, since it uses as much as digits as its factorization.

1557481649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1209600, while the sum is 50.

The square root of 1557481649 is about 39464.9420245362. The cubic root of 1557481649 is about 1159.1535762036.

The spelling of 1557481649 in words is "one billion, five hundred fifty-seven million, four hundred eighty-one thousand, six hundred forty-nine".