2173221994581 has 32 divisors (see below), whose sum is σ = 3578547392640. Its totient is φ = 1292253206400.

The previous prime is 2173221994549. The next prime is 2173221994583. The reversal of 2173221994581 is 1854991223712.

2173221994581 is a `hidden beast` number, since 2 + 1 + 7 + 32 + 21 + 9 + 9 + 4 + 581 = 666.

It is not a de Polignac number, because 2173221994581 - 2⁵ = 2173221994549 is a prime.

It is a super-2 number, since 2×2173221994581² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2173221994583) 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 31 ways as a sum of consecutive naturals, for example, 69014880 + ... + 69046361.

It is an arithmetic number, because the mean of its divisors is an integer number (111829606020).

Almost surely, 2^{2173221994581} is an apocalyptic number.

It is an amenable number.

2173221994581 is a deficient number, since it is larger than the sum of its proper divisors (1405325398059).

2173221994581 is a wasteful number, since it uses less digits than its factorization.

2173221994581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138061314 (or 138061308 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 54.

The spelling of 2173221994581 in words is "two trillion, one hundred seventy-three billion, two hundred twenty-one million, nine hundred ninety-four thousand, five hundred eighty-one".