2161855680810 has 48 divisors (see below), whose sum is σ = 6035548108896. Its totient is φ = 494138440992.

The previous prime is 2161855680731. The next prime is 2161855680811. The reversal of 2161855680810 is 180865581612.

It is a super-2 number, since 2×2161855680810² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2161855680811) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 735323592 + ... + 735326531.

It is an arithmetic number, because the mean of its divisors is an integer number (125740585602).

Almost surely, 2^{2161855680810} is an apocalyptic number.

2161855680810 is an abundant number, since it is smaller than the sum of its proper divisors (3873692428086).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2161855680810 is a wasteful number, since it uses less digits than its factorization.

2161855680810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1470650147 (or 1470650140 counting only the distinct ones).

The product of its (nonzero) digits is 921600, while the sum is 51.

The spelling of 2161855680810 in words is "two trillion, one hundred sixty-one billion, eight hundred fifty-five million, six hundred eighty thousand, eight hundred ten".