2001771161 has 4 divisors (see below), whose sum is σ = 2155753572. Its totient is φ = 1847788752.

The previous prime is 2001771133. The next prime is 2001771169. The reversal of 2001771161 is 1611771002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1611771002 = 2 ⋅805885501.

It can be written as a sum of positive squares in 2 ways, for example, as 381225625 + 1620545536 = 19525^2 + 40256^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001771161 is a prime.

It is a super-2 number, since 2×2001771161² = 8014175562022575842, which contains 22 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 2001771161.

It is not an unprimeable number, because it can be changed into a prime (2001771169) 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, 76991186 + ... + 76991211.

It is an arithmetic number, because the mean of its divisors is an integer number (538938393).

Almost surely, 2^2001771161 is an apocalyptic number.

It is an amenable number.

2001771161 is a deficient number, since it is larger than the sum of its proper divisors (153982411).

2001771161 is a wasteful number, since it uses less digits than its factorization.

2001771161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153982410.

The product of its (nonzero) digits is 588, while the sum is 26.

The square root of 2001771161 is about 44741.1573498049. The cubic root of 2001771161 is about 1260.2928606648.

The spelling of 2001771161 in words is "two billion, one million, seven hundred seventy-one thousand, one hundred sixty-one".