51511616 has 56 divisors (see below), whose sum is σ = 111352584. Its totient is φ = 23500800.

The previous prime is 51511609. The next prime is 51511637. The reversal of 51511616 is 61611515.

It can be written as a sum of positive squares in 4 ways, for example, as 817216 + 50694400 = 904^2 + 7120^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

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, 83726 + ... + 84338.

It is an arithmetic number, because the mean of its divisors is an integer number (1988439).

Almost surely, 2^51511616 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 51511616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55676292).

51511616 is an abundant number, since it is smaller than the sum of its proper divisors (59840968).

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

51511616 is a wasteful number, since it uses less digits than its factorization.

51511616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 739 (or 729 counting only the distinct ones).

The product of its digits is 900, while the sum is 26.

The square root of 51511616 is about 7177.1593266417. The cubic root of 51511616 is about 372.0789133855.

The spelling of 51511616 in words is "fifty-one million, five hundred eleven thousand, six hundred sixteen".