1813881 has 8 divisors (see below), whose sum is σ = 2477664. Its totient is φ = 1179680.

The previous prime is 1813853. The next prime is 1813897. The reversal of 1813881 is 1883181.

1813881 = T₁₆₈ + T₁₆₉ + ... + T₂₄₉.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1813881 - 2⁶ = 1813817 is a prime.

It is a super-2 number, since 2×1813881² = 6580328564322, which contains 22 as substring.

It is an Ulam number.

1813881 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1813081) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7251 + ... + 7496.

It is an arithmetic number, because the mean of its divisors is an integer number (309708).

2^1813881 is an apocalyptic number.

It is an amenable number.

1813881 is a deficient number, since it is larger than the sum of its proper divisors (663783).

1813881 is a wasteful number, since it uses less digits than its factorization.

1813881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14791.

The product of its digits is 1536, while the sum is 30.

The square root of 1813881 is about 1346.8039946481. The cubic root of 1813881 is about 121.9559323060.

The spelling of 1813881 in words is "one million, eight hundred thirteen thousand, eight hundred eighty-one".