18400038228 has 144 divisors (see below), whose sum is σ = 55413251712. Its totient is φ = 5074272000.

The previous prime is 18400038221. The next prime is 18400038229. The reversal of 18400038228 is 82283000481.

It is a happy number.

It is a super-2 number, since 2×18400038228² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18400038192 and 18400038201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18400038221) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 340338 + ... + 390678.

It is an arithmetic number, because the mean of its divisors is an integer number (384814248).

Almost surely, 2^18400038228 is an apocalyptic number.

18400038228 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18400038228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27706625856).

18400038228 is an abundant number, since it is smaller than the sum of its proper divisors (37013213484).

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

18400038228 is a wasteful number, since it uses less digits than its factorization.

18400038228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50446 (or 50441 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 36.

The spelling of 18400038228 in words is "eighteen billion, four hundred million, thirty-eight thousand, two hundred twenty-eight".