18931238352 has 400 divisors, whose sum is σ = 63025622352. Its totient is φ = 5434490880.

The previous prime is 18931238341. The next prime is 18931238353. The reversal of 18931238352 is 25383213981.

It can be written as a sum of positive squares in 8 ways, for example, as 4551391296 + 14379847056 = 67464^2 + 119916^2 .

It is a junction number, because it is equal to n+sod(n) for n = 18931238298 and 18931238307.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18931238353) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 44967102 + ... + 44967522.

Almost surely, 2^18931238352 is an apocalyptic number.

18931238352 is a gapful number since it is divisible by the number (12) 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 18931238352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31512811176).

18931238352 is an abundant number, since it is smaller than the sum of its proper divisors (44094384000).

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

18931238352 is a wasteful number, since it uses less digits than its factorization.

18931238352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 628 (or 613 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The spelling of 18931238352 in words is "eighteen billion, nine hundred thirty-one million, two hundred thirty-eight thousand, three hundred fifty-two".