51639380 has 24 divisors (see below), whose sum is σ = 116785032. Its totient is φ = 19066752.

The previous prime is 51639349. The next prime is 51639389. The reversal of 51639380 is 8393615.

51639380 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 7496644 + 44142736 = 2738^2 + 6644^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 51639380.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51639389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 99047 + ... + 99566.

It is an arithmetic number, because the mean of its divisors is an integer number (4866043).

Almost surely, 2^51639380 is an apocalyptic number.

It is an amenable number.

51639380 is an abundant number, since it is smaller than the sum of its proper divisors (65145652).

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

51639380 is a wasteful number, since it uses less digits than its factorization.

51639380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198635 (or 198633 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 51639380 is about 7186.0545503078. The cubic root of 51639380 is about 372.3862812186.

The spelling of 51639380 in words is "fifty-one million, six hundred thirty-nine thousand, three hundred eighty".