18311958 has 96 divisors (see below), whose sum is σ = 49061376. Its totient is φ = 4817664.

The previous prime is 18311957. The next prime is 18311983. The reversal of 18311958 is 85911381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18311957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 177735 + ... + 177837.

It is an arithmetic number, because the mean of its divisors is an integer number (511056).

Almost surely, 2^18311958 is an apocalyptic number.

18311958 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18311958, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24530688).

18311958 is an abundant number, since it is smaller than the sum of its proper divisors (30749418).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18311958 is a wasteful number, since it uses less digits than its factorization.

18311958 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218 (or 215 counting only the distinct ones).

The product of its digits is 8640, while the sum is 36.

The square root of 18311958 is about 4279.2473637312. The cubic root of 18311958 is about 263.5794785854.

The spelling of 18311958 in words is "eighteen million, three hundred eleven thousand, nine hundred fifty-eight".