2161571796997 has 4 divisors (see below), whose sum is σ = 2161580545260. Its totient is φ = 2161563048736.

The previous prime is 2161571796893. The next prime is 2161571797003. The reversal of 2161571796997 is 7996971751612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1510308270916 + 651263526081 = 1228946^2 + 807009^2 .

It is a cyclic number.

It is not a de Polignac number, because 2161571796997 - 2⁷ = 2161571796869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2161571596997) 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, 3992398 + ... + 4501375.

It is an arithmetic number, because the mean of its divisors is an integer number (540395136315).

Almost surely, 2^{2161571796997} is an apocalyptic number.

It is an amenable number.

2161571796997 is a deficient number, since it is larger than the sum of its proper divisors (8748263).

2161571796997 is an equidigital number, since it uses as much as digits as its factorization.

2161571796997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8748262.

The product of its digits is 90016920, while the sum is 70.

The spelling of 2161571796997 in words is "two trillion, one hundred sixty-one billion, five hundred seventy-one million, seven hundred ninety-six thousand, nine hundred ninety-seven".