1557481609 has 2 divisors, whose sum is σ = 1557481610. Its totient is φ = 1557481608.

The previous prime is 1557481591. The next prime is 1557481649. The reversal of 1557481609 is 9061847551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1242774009 + 314707600 = 35253^2 + 17740^2 .

It is a cyclic number.

It is not a de Polignac number, because 1557481609 - 2²³ = 1549093001 is a prime.

It is not a weakly prime, because it can be changed into another prime (1557481649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 778740804 + 778740805.

It is an arithmetic number, because the mean of its divisors is an integer number (778740805).

Almost surely, 2^1557481609 is an apocalyptic number.

It is an amenable number.

1557481609 is a deficient number, since it is larger than the sum of its proper divisors (1).

1557481609 is an equidigital number, since it uses as much as digits as its factorization.

1557481609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 302400, while the sum is 46.

The square root of 1557481609 is about 39464.9415177573. The cubic root of 1557481609 is about 1159.1535662803.

The spelling of 1557481609 in words is "one billion, five hundred fifty-seven million, four hundred eighty-one thousand, six hundred nine".