1918881 has 6 divisors (see below), whose sum is σ = 2771730. Its totient is φ = 1279248.

The previous prime is 1918879. The next prime is 1918897. The reversal of 1918881 is 1888191.

It can be written as a sum of positive squares in only one way, i.e., 968256 + 950625 = 984^2 + 975^2 .

It is not a de Polignac number, because 1918881 - 2¹ = 1918879 is a prime.

It is a super-2 number, since 2×1918881² = 7364208584322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1918811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 106596 + ... + 106613.

It is an arithmetic number, because the mean of its divisors is an integer number (461955).

2^1918881 is an apocalyptic number.

It is an amenable number.

1918881 is a deficient number, since it is larger than the sum of its proper divisors (852849).

1918881 is a wasteful number, since it uses less digits than its factorization.

1918881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213215 (or 213212 counting only the distinct ones).

The product of its digits is 4608, while the sum is 36.

The square root of 1918881 is about 1385.2368028608. The cubic root of 1918881 is about 124.2651497599.

The spelling of 1918881 in words is "one million, nine hundred eighteen thousand, eight hundred eighty-one".