51302640 has 80 divisors (see below), whose sum is σ = 160052256. Its totient is φ = 13593600.

The previous prime is 51302633. The next prime is 51302659. The reversal of 51302640 is 4620315.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42850 + ... + 44030.

Almost surely, 2^51302640 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 51302640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80026128).

51302640 is an abundant number, since it is smaller than the sum of its proper divisors (108749616).

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

51302640 is a wasteful number, since it uses less digits than its factorization.

51302640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1378 (or 1372 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 51302640 is about 7162.5861251366. The cubic root of 51302640 is about 371.5750726677.

Adding to 51302640 its reverse (4620315), we get a palindrome (55922955).

The spelling of 51302640 in words is "fifty-one million, three hundred two thousand, six hundred forty".