18720234 has 48 divisors (see below), whose sum is σ = 45313632. Its totient is φ = 5758128.

The previous prime is 18720227. The next prime is 18720239. The reversal of 18720234 is 43202781.

It is a super-2 number, since 2×18720234² = 700894322029512, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 18720198 and 18720207.

It is not an unprimeable number, because it can be changed into a prime (18720239) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4837 + ... + 7799.

It is an arithmetic number, because the mean of its divisors is an integer number (944034).

Almost surely, 2^18720234 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18720234, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22656816).

18720234 is an abundant number, since it is smaller than the sum of its proper divisors (26593398).

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

18720234 is a wasteful number, since it uses less digits than its factorization.

18720234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2993 (or 2981 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 18720234 is about 4326.6885721068. The cubic root of 18720234 is about 265.5239851931.

The spelling of 18720234 in words is "eighteen million, seven hundred twenty thousand, two hundred thirty-four".