2157286656681 has 48 divisors (see below), whose sum is σ = 3592327764480. Its totient is φ = 1284736412160.

The previous prime is 2157286656661. The next prime is 2157286656689. The reversal of 2157286656681 is 1866566827512.

2157286656681 is a `hidden beast` number, since 2 + 1 + 5 + 7 + 2 + 8 + 66 + 566 + 8 + 1 = 666.

It is not a de Polignac number, because 2157286656681 - 2²⁶ = 2157219547817 is a prime.

It is a super-2 number, since 2×2157286656681² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2157286656689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 10916616 + ... + 11112473.

It is an arithmetic number, because the mean of its divisors is an integer number (74840161760).

Almost surely, 2^{2157286656681} is an apocalyptic number.

It is an amenable number.

2157286656681 is a deficient number, since it is larger than the sum of its proper divisors (1435041107799).

2157286656681 is a wasteful number, since it uses less digits than its factorization.

2157286656681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22029148 (or 22029136 counting only the distinct ones).

The product of its digits is 58060800, while the sum is 63.

The spelling of 2157286656681 in words is "two trillion, one hundred fifty-seven billion, two hundred eighty-six million, six hundred fifty-six thousand, six hundred eighty-one".