51399664 has 40 divisors (see below), whose sum is σ = 104591520. Its totient is φ = 24423168.

The previous prime is 51399661. The next prime is 51399703. The reversal of 51399664 is 46699315.

It is a self number, because there is not a number n which added to its sum of digits gives 51399664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51399661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72142 + ... + 72850.

It is an arithmetic number, because the mean of its divisors is an integer number (2614788).

Almost surely, 2^51399664 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 51399664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52295760).

51399664 is an abundant number, since it is smaller than the sum of its proper divisors (53191856).

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

51399664 is a wasteful number, since it uses less digits than its factorization.

51399664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 937 (or 931 counting only the distinct ones).

The product of its digits is 174960, while the sum is 43.

The square root of 51399664 is about 7169.3558985449. The cubic root of 51399664 is about 371.8091671614.

The spelling of 51399664 in words is "fifty-one million, three hundred ninety-nine thousand, six hundred sixty-four".