51443640 has 256 divisors, whose sum is σ = 190080000. Its totient is φ = 12317184.

The previous prime is 51443633. The next prime is 51443669. The reversal of 51443640 is 4634415.

51443640 is a `hidden beast` number, since 5 + 14 + 4 + 3 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Saint-Exupery number, since it is equal to the product of the sides of a Pythagorean triangle: 545 × 513 × 184.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 471906 + ... + 472014.

It is an arithmetic number, because the mean of its divisors is an integer number (742500).

Almost surely, 2^51443640 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 51443640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95040000).

51443640 is an abundant number, since it is smaller than the sum of its proper divisors (138636360).

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

51443640 is a wasteful number, since it uses less digits than its factorization.

51443640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 51443640 is about 7172.4221850084. The cubic root of 51443640 is about 371.9151731663.

The spelling of 51443640 in words is "fifty-one million, four hundred forty-three thousand, six hundred forty".