51215680 has 28 divisors (see below), whose sum is σ = 121958100. Its totient is φ = 20486144.

The previous prime is 51215677. The next prime is 51215693. The reversal of 51215680 is 8651215.

It can be written as a sum of positive squares in 2 ways, for example, as 40246336 + 10969344 = 6344^2 + 3312^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79705 + ... + 80344.

Almost surely, 2^51215680 is an apocalyptic number.

It is an amenable number.

51215680 is an abundant number, since it is smaller than the sum of its proper divisors (70742420).

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

51215680 is a wasteful number, since it uses less digits than its factorization.

51215680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160066 (or 160056 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 51215680 is about 7156.5131174337. The cubic root of 51215680 is about 371.3650091289.

Adding to 51215680 its reverse (8651215), we get a palindrome (59866895).

It can be divided in two parts, 5121 and 5680, that added together give a palindrome (10801).

The spelling of 51215680 in words is "fifty-one million, two hundred fifteen thousand, six hundred eighty".