1881994185 has 12 divisors (see below), whose sum is σ = 3262123332. Its totient is φ = 1003730208.

The previous prime is 1881994181. The next prime is 1881994189. The reversal of 1881994185 is 5814991881.

It is an interprime number because it is at equal distance from previous prime (1881994181) and next prime (1881994189).

It can be written as a sum of positive squares in 2 ways, for example, as 1505129616 + 376864569 = 38796^2 + 19413^2 .

It is not a de Polignac number, because 1881994185 - 2² = 1881994181 is a prime.

It is a super-2 number, since 2×1881994185² = 7083804224747628450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1881994181) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20911002 + ... + 20911091.

It is an arithmetic number, because the mean of its divisors is an integer number (271843611).

Almost surely, 2^1881994185 is an apocalyptic number.

1881994185 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1881994185 is a deficient number, since it is larger than the sum of its proper divisors (1380129147).

1881994185 is a wasteful number, since it uses less digits than its factorization.

1881994185 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41822104 (or 41822101 counting only the distinct ones).

The product of its digits is 829440, while the sum is 54.

The square root of 1881994185 is about 43381.9569060687. The cubic root of 1881994185 is about 1234.6373918377.

The spelling of 1881994185 in words is "one billion, eight hundred eighty-one million, nine hundred ninety-four thousand, one hundred eighty-five".