51423840 has 288 divisors, whose sum is σ = 196481376. Its totient is φ = 12165120.

The previous prime is 51423811. The next prime is 51423851. The reversal of 51423840 is 4832415.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×51423840² = 5288822640691200, which contains 22 as substring.

It is a nialpdrome in base 13.

It is a congruent number.

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, 767487 + ... + 767553.

It is an arithmetic number, because the mean of its divisors is an integer number (682227).

Almost surely, 2^51423840 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 51423840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98240688).

51423840 is an abundant number, since it is smaller than the sum of its proper divisors (145057536).

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

51423840 is a wasteful number, since it uses less digits than its factorization.

51423840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142 (or 131 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 51423840 is about 7171.0417653225. The cubic root of 51423840 is about 371.8674519100.

The spelling of 51423840 in words is "fifty-one million, four hundred twenty-three thousand, eight hundred forty".