51231840 has 192 divisors, whose sum is σ = 182310912. Its totient is φ = 11980800.

The previous prime is 51231839. The next prime is 51231841. The reversal of 51231840 is 4813215.

It is an interprime number because it is at equal distance from previous prime (51231839) and next prime (51231841).

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 51231840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51231841) 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, 163524 + ... + 163836.

It is an arithmetic number, because the mean of its divisors is an integer number (949536).

Almost surely, 2^51231840 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 51231840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91155456).

51231840 is an abundant number, since it is smaller than the sum of its proper divisors (131079072).

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

51231840 is a wasteful number, since it uses less digits than its factorization.

51231840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373 (or 365 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 51231840 is about 7157.6420698440. The cubic root of 51231840 is about 371.4040637535.

The spelling of 51231840 in words is "fifty-one million, two hundred thirty-one thousand, eight hundred forty".