18219831 has 16 divisors (see below), whose sum is σ = 28410624. Its totient is φ = 10168704.

The previous prime is 18219827. The next prime is 18219833. The reversal of 18219831 is 13891281.

It is not a de Polignac number, because 18219831 - 2² = 18219827 is a prime.

It is a super-2 number, since 2×18219831² = 663924483337122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18219792 and 18219801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18219833) 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 15 ways as a sum of consecutive naturals, for example, 9186 + ... + 10991.

It is an arithmetic number, because the mean of its divisors is an integer number (1775664).

Almost surely, 2^18219831 is an apocalyptic number.

18219831 is a deficient number, since it is larger than the sum of its proper divisors (10190793).

18219831 is a wasteful number, since it uses less digits than its factorization.

18219831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20230.

The product of its digits is 3456, while the sum is 33.

The square root of 18219831 is about 4268.4693978053. The cubic root of 18219831 is about 263.1367146666.

The spelling of 18219831 in words is "eighteen million, two hundred nineteen thousand, eight hundred thirty-one".