51723240 has 128 divisors (see below), whose sum is σ = 163296000. Its totient is φ = 13088768.

The previous prime is 51723229. The next prime is 51723247. The reversal of 51723240 is 4232715.

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 51723240.

It is not an unprimeable number, because it can be changed into a prime (51723247) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 309637 + ... + 309803.

It is an arithmetic number, because the mean of its divisors is an integer number (1275750).

Almost surely, 2^51723240 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 51723240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81648000).

51723240 is an abundant number, since it is smaller than the sum of its proper divisors (111572760).

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

51723240 is a wasteful number, since it uses less digits than its factorization.

51723240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299 (or 295 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 51723240 is about 7191.8870958880. The cubic root of 51723240 is about 372.5877516489.

Adding to 51723240 its reverse (4232715), we get a palindrome (55955955).

The spelling of 51723240 in words is "fifty-one million, seven hundred twenty-three thousand, two hundred forty".