51400440 has 256 divisors, whose sum is σ = 211276800. Its totient is φ = 10824192.

The previous prime is 51400439. The next prime is 51400451. The reversal of 51400440 is 4400415.

It is a Harshad number since it is a multiple of its sum of digits (18).

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, 98019 + ... + 98541.

It is an arithmetic number, because the mean of its divisors is an integer number (825300).

Almost surely, 2^51400440 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 51400440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105638400).

51400440 is an abundant number, since it is smaller than the sum of its proper divisors (159876360).

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

51400440 is a wasteful number, since it uses less digits than its factorization.

51400440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 563 (or 553 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 51400440 is about 7169.4100175677. The cubic root of 51400440 is about 371.8110382661.

Adding to 51400440 its reverse (4400415), we get a palindrome (55800855).

The spelling of 51400440 in words is "fifty-one million, four hundred thousand, four hundred forty".