23281440 has 288 divisors, whose sum is σ = 92969856. Its totient is φ = 4792320.

The previous prime is 23281439. The next prime is 23281457. The reversal of 23281440 is 4418232.

It is a super-3 number, since 3×23281440³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 23281440.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 567820 + ... + 567860.

It is an arithmetic number, because the mean of its divisors is an integer number (322812).

Almost surely, 2^23281440 is an apocalyptic number.

23281440 is a gapful number since it is divisible by the number (20) 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 23281440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46484928).

23281440 is an abundant number, since it is smaller than the sum of its proper divisors (69688416).

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

23281440 is a wasteful number, since it uses less digits than its factorization.

23281440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 23281440 is about 4825.0844552194. The cubic root of 23281440 is about 285.5419665685.

Adding to 23281440 its reverse (4418232), we get a palindrome (27699672).

The spelling of 23281440 in words is "twenty-three million, two hundred eighty-one thousand, four hundred forty".