72123840 has 168 divisors, whose sum is σ = 252008640. Its totient is φ = 18929664.

The previous prime is 72123839. The next prime is 72123847. The reversal of 72123840 is 4832127.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72123847) 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, 227362 + ... + 227678.

Almost surely, 2^72123840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 72123840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126004320).

72123840 is an abundant number, since it is smaller than the sum of its proper divisors (179884800).

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

72123840 is a wasteful number, since it uses less digits than its factorization.

72123840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419 (or 406 counting only the distinct ones).

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

The square root of 72123840 is about 8492.5755810590. The cubic root of 72123840 is about 416.2551442699.

Adding to 72123840 its reverse (4832127), we get a palindrome (76955967).

The spelling of 72123840 in words is "seventy-two million, one hundred twenty-three thousand, eight hundred forty".