1881951161 has 4 divisors (see below), whose sum is σ = 1882385892. Its totient is φ = 1881516432.

The previous prime is 1881951157. The next prime is 1881951173. The reversal of 1881951161 is 1611591881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1611591881 = 193 ⋅8350217.

It can be written as a sum of positive squares in 2 ways, for example, as 1072890025 + 809061136 = 32755^2 + 28444^2 .

It is a cyclic number.

It is not a de Polignac number, because 1881951161 - 2² = 1881951157 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1881951101) 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, 210806 + ... + 219551.

It is an arithmetic number, because the mean of its divisors is an integer number (470596473).

Almost surely, 2^1881951161 is an apocalyptic number.

It is an amenable number.

1881951161 is a deficient number, since it is larger than the sum of its proper divisors (434731).

1881951161 is an equidigital number, since it uses as much as digits as its factorization.

1881951161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434730.

The product of its digits is 17280, while the sum is 41.

The square root of 1881951161 is about 43381.4610288773. The cubic root of 1881951161 is about 1234.6279834764.

The spelling of 1881951161 in words is "one billion, eight hundred eighty-one million, nine hundred fifty-one thousand, one hundred sixty-one".