51355840 has 84 divisors (see below), whose sum is σ = 127119888. Its totient is φ = 19760640.

The previous prime is 51355831. The next prime is 51355853. The reversal of 51355840 is 4855315.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 307437 + ... + 307603.

It is an arithmetic number, because the mean of its divisors is an integer number (1513332).

Almost surely, 2^51355840 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 51355840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63559944).

51355840 is an abundant number, since it is smaller than the sum of its proper divisors (75764048).

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

51355840 is a wasteful number, since it uses less digits than its factorization.

51355840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246 (or 205 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 31.

The square root of 51355840 is about 7166.2989052927. The cubic root of 51355840 is about 371.7034673913.

The spelling of 51355840 in words is "fifty-one million, three hundred fifty-five thousand, eight hundred forty".