2157197575681 has 4 divisors (see below), whose sum is σ = 2166223507200. Its totient is φ = 2148171644164.

The previous prime is 2157197575669. The next prime is 2157197575691. The reversal of 2157197575681 is 1865757917512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2157197575681 - 2¹¹ = 2157197573633 is a prime.

It is a super-2 number, since 2×2157197575681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2157197575691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4512965401 + ... + 4512965878.

It is an arithmetic number, because the mean of its divisors is an integer number (541555876800).

Almost surely, 2^{2157197575681} is an apocalyptic number.

It is an amenable number.

2157197575681 is a deficient number, since it is larger than the sum of its proper divisors (9025931519).

2157197575681 is an equidigital number, since it uses as much as digits as its factorization.

2157197575681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9025931518.

The product of its digits is 37044000, while the sum is 64.

The spelling of 2157197575681 in words is "two trillion, one hundred fifty-seven billion, one hundred ninety-seven million, five hundred seventy-five thousand, six hundred eighty-one".