2161150071661 has 4 divisors (see below), whose sum is σ = 2469885796192. Its totient is φ = 1852414347132.

The previous prime is 2161150071643. The next prime is 2161150071679. The reversal of 2161150071661 is 1661700511612.

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 an interprime number because it is at equal distance from previous prime (2161150071643) and next prime (2161150071679).

It is a cyclic number.

It is not a de Polignac number, because 2161150071661 - 2¹¹ = 2161150069613 is a prime.

It is a super-3 number, since 3×2161150071661³ (a number of 38 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2161150071661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2161150071601) 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, 154367862255 + ... + 154367862268.

It is an arithmetic number, because the mean of its divisors is an integer number (617471449048).

Almost surely, 2^{2161150071661} is an apocalyptic number.

It is an amenable number.

2161150071661 is a deficient number, since it is larger than the sum of its proper divisors (308735724531).

2161150071661 is an equidigital number, since it uses as much as digits as its factorization.

2161150071661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308735724530.

The product of its (nonzero) digits is 15120, while the sum is 37.

The spelling of 2161150071661 in words is "two trillion, one hundred sixty-one billion, one hundred fifty million, seventy-one thousand, six hundred sixty-one".