51315664 has 40 divisors (see below), whose sum is σ = 103271168. Its totient is φ = 24675840.

The previous prime is 51315661. The next prime is 51315683. The reversal of 51315664 is 46651315.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51315661) 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, 152104 + ... + 152440.

Almost surely, 2^51315664 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 51315664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51635584).

51315664 is an abundant number, since it is smaller than the sum of its proper divisors (51955504).

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

51315664 is a wasteful number, since it uses less digits than its factorization.

51315664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683 (or 677 counting only the distinct ones).

The product of its digits is 10800, while the sum is 31.

The square root of 51315664 is about 7163.4952362656. The cubic root of 51315664 is about 371.6065134427.

Adding to 51315664 its reverse (46651315), we get a palindrome (97966979).

The spelling of 51315664 in words is "fifty-one million, three hundred fifteen thousand, six hundred sixty-four".