1557012681 has 27 divisors (see below), whose sum is σ = 2617598061. Its totient is φ = 889248024.

The previous prime is 1557012673. The next prime is 1557012701. The reversal of 1557012681 is 1862107551.

The square root of 1557012681 is 39459.

It is a perfect power (a square), and thus also a powerful number.

1557012681 is a `hidden beast` number, since 1 + 5 + 570 + 1 + 2 + 6 + 81 = 666.

It is not a de Polignac number, because 1557012681 - 2³ = 1557012673 is a prime.

It is a super-2 number, since 2×1557012681² = 4848576977589615522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1557012181) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 827700 + ... + 829578.

Almost surely, 2^1557012681 is an apocalyptic number.

1557012681 is the 39459-th square number.

1557012681 is the 19730-th centered octagonal number.

It is an amenable number.

1557012681 is a deficient number, since it is larger than the sum of its proper divisors (1060585380).

1557012681 is an frugal number, since it uses more digits than its factorization.

1557012681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3778 (or 1889 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 36.

The cubic root of 1557012681 is about 1159.0372215947.

Multiplying 1557012681 by its sum of digits (36), we get a square (56052456516 = 236754²).

The spelling of 1557012681 in words is "one billion, five hundred fifty-seven million, twelve thousand, six hundred eighty-one".