51081680 has 40 divisors (see below), whose sum is σ = 127903272. Its totient is φ = 18860544.

The previous prime is 51081661. The next prime is 51081691. The reversal of 51081680 is 8618015.

It can be written as a sum of positive squares in 4 ways, for example, as 6512704 + 44568976 = 2552^2 + 6676^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23519 + ... + 25598.

Almost surely, 2^51081680 is an apocalyptic number.

It is an amenable number.

51081680 is an abundant number, since it is smaller than the sum of its proper divisors (76821592).

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

51081680 is a wasteful number, since it uses less digits than its factorization.

51081680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49143 (or 49137 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 29.

The square root of 51081680 is about 7147.1448844976. The cubic root of 51081680 is about 371.0408481553.

Adding to 51081680 its reverse (8618015), we get a palindrome (59699695).

The spelling of 51081680 in words is "fifty-one million, eighty-one thousand, six hundred eighty".