51561516 has 48 divisors (see below), whose sum is σ = 128822400. Its totient is φ = 16002432.

The previous prime is 51561511. The next prime is 51561529. The reversal of 51561516 is 61516515.

It is not an unprimeable number, because it can be changed into a prime (51561511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11536 + ... + 15368.

It is an arithmetic number, because the mean of its divisors is an integer number (2683800).

Almost surely, 2^51561516 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 51561516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (64411200).

51561516 is an abundant number, since it is smaller than the sum of its proper divisors (77260884).

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

51561516 is a wasteful number, since it uses less digits than its factorization.

51561516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3918 (or 3916 counting only the distinct ones).

The product of its digits is 4500, while the sum is 30.

The square root of 51561516 is about 7180.6347908803. The cubic root of 51561516 is about 372.1990205714.

The spelling of 51561516 in words is "fifty-one million, five hundred sixty-one thousand, five hundred sixteen".