1557256563 has 16 divisors (see below), whose sum is σ = 2317130400.
Its totient is φ = 1033633440.
The previous prime is 1557256543. The next prime is 1557256621. The reversal of 1557256563 is 3656527551.
1557256563 is a `hidden beast` number, since 15 + 5 + 72 + 5 + 6 + 563 = 666.
It is not a de Polignac number, because 1557256563 - 25 = 1557256531 is a prime.
It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.
It is not an unprimeable number, because it can be changed into a prime (1557256543) by changing a digit.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 119748 + ... + 132113.
It is an arithmetic number, because the mean of its divisors is an integer number (144820650).
Almost surely, 21557256563 is an apocalyptic number.
1557256563 is a deficient number, since it is larger than the sum of its proper divisors (759873837).
1557256563 is a wasteful number, since it uses less digits than its factorization.
1557256563 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 252099 (or 252093 counting only the distinct ones).
The product of its digits is 945000, while the sum is 45.
The square root of 1557256563 is about 39462.0902005963.
The cubic root of 1557256563 is about 1159.0977335314.
The spelling of 1557256563 in words is "one billion, five hundred fifty-seven million, two hundred fifty-six thousand, five hundred sixty-three".