51640416 has 144 divisors (see below), whose sum is σ = 158230800. Its totient is φ = 16547328.

The previous prime is 51640411. The next prime is 51640417. The reversal of 51640416 is 61404615.

51640416 is a `hidden beast` number, since 5 + 1 + 640 + 4 + 16 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

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

It is a self number, because there is not a number n which added to its sum of digits gives 51640416.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51640411) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 225390 + ... + 225618.

It is an arithmetic number, because the mean of its divisors is an integer number (1098825).

Almost surely, 2^51640416 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 51640416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (79115400).

51640416 is an abundant number, since it is smaller than the sum of its proper divisors (106590384).

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

51640416 is a wasteful number, since it uses less digits than its factorization.

51640416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283 (or 263 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 51640416 is about 7186.1266340081. The cubic root of 51640416 is about 372.3887714990.

The spelling of 51640416 in words is "fifty-one million, six hundred forty thousand, four hundred sixteen".