5181981 has 32 divisors (see below), whose sum is σ = 8355840. Its totient is φ = 2794176.

The previous prime is 5181977. The next prime is 5181983. The reversal of 5181981 is 1891815.

It is not a de Polignac number, because 5181981 - 2² = 5181977 is a prime.

It is a super-2 number, since 2×5181981² = 53705854168722, which contains 22 as substring.

5181981 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5181983) 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 31 ways as a sum of consecutive naturals, for example, 40740 + ... + 40866.

It is an arithmetic number, because the mean of its divisors is an integer number (261120).

Almost surely, 2^5181981 is an apocalyptic number.

It is an amenable number.

5181981 is a deficient number, since it is larger than the sum of its proper divisors (3173859).

5181981 is a wasteful number, since it uses less digits than its factorization.

5181981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233.

The product of its digits is 2880, while the sum is 33.

The square root of 5181981 is about 2276.3964944622. The cubic root of 5181981 is about 173.0474771406.

The spelling of 5181981 in words is "five million, one hundred eighty-one thousand, nine hundred eighty-one".