51515780 has 24 divisors (see below), whose sum is σ = 114547608. Its totient is φ = 19394048.

The previous prime is 51515773. The next prime is 51515801. The reversal of 51515780 is 8751515.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 27857284 + 23658496 = 5278^2 + 4864^2 .

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, 75419 + ... + 76098.

It is an arithmetic number, because the mean of its divisors is an integer number (4772817).

Almost surely, 2^51515780 is an apocalyptic number.

It is an amenable number.

51515780 is an abundant number, since it is smaller than the sum of its proper divisors (63031828).

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

51515780 is a wasteful number, since it uses less digits than its factorization.

51515780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151543 (or 151541 counting only the distinct ones).

The product of its (nonzero) digits is 7000, while the sum is 32.

The square root of 51515780 is about 7177.4494076935. The cubic root of 51515780 is about 372.0889389226.

The spelling of 51515780 in words is "fifty-one million, five hundred fifteen thousand, seven hundred eighty".