51581520 has 120 divisors (see below), whose sum is σ = 178893312. Its totient is φ = 13305600.

The previous prime is 51581501. The next prime is 51581533. The reversal of 51581520 is 2518515.

51581520 = T₁₈₅ + T₁₈₆ + ... + T₆₈₀.

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21165 + ... + 23475.

Almost surely, 2^51581520 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 51581520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89446656).

51581520 is an abundant number, since it is smaller than the sum of its proper divisors (127311792).

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

51581520 is a wasteful number, since it uses less digits than its factorization.

51581520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2361 (or 2352 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 27.

The square root of 51581520 is about 7182.0275688694. The cubic root of 51581520 is about 372.2471475929.

The spelling of 51581520 in words is "fifty-one million, five hundred eighty-one thousand, five hundred twenty".