51131520 has 256 divisors, whose sum is σ = 198288000. Its totient is φ = 12349440.

The previous prime is 51131501. The next prime is 51131537. The reversal of 51131520 is 2513115.

51131520 is a `hidden beast` number, since 511 + 3 + 152 + 0 = 666.

It is a super-2 number, since 2×51131520² = 5228864675020800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 51131493 and 51131502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 189946 + ... + 190214.

Almost surely, 2^51131520 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 51131520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99144000).

51131520 is an abundant number, since it is smaller than the sum of its proper divisors (147156480).

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

51131520 is a wasteful number, since it uses less digits than its factorization.

51131520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308 (or 290 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 18.

The square root of 51131520 is about 7150.6307414102. The cubic root of 51131520 is about 371.1614828247.

Adding to 51131520 its reverse (2513115), we get a palindrome (53644635).

The spelling of 51131520 in words is "fifty-one million, one hundred thirty-one thousand, five hundred twenty".