1557256561 has 32 divisors (see below), whose sum is σ = 1916006400. Its totient is φ = 1236903360.

The previous prime is 1557256543. The next prime is 1557256621. The reversal of 1557256561 is 1656527551.

It is not a de Polignac number, because 1557256561 - 2⁷ = 1557256433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1557256531) 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 in 31 ways as a sum of consecutive naturals, for example, 673275 + ... + 675583.

It is an arithmetic number, because the mean of its divisors is an integer number (59875200).

Almost surely, 2^1557256561 is an apocalyptic number.

It is an amenable number.

1557256561 is a deficient number, since it is larger than the sum of its proper divisors (358749839).

1557256561 is a wasteful number, since it uses less digits than its factorization.

1557256561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2469.

The product of its digits is 315000, while the sum is 43.

The square root of 1557256561 is about 39462.0901752555. The cubic root of 1557256561 is about 1159.0977330352.

The spelling of 1557256561 in words is "one billion, five hundred fifty-seven million, two hundred fifty-six thousand, five hundred sixty-one".