51491232 has 144 divisors (see below), whose sum is σ = 167174280. Its totient is φ = 14893056.

The previous prime is 51491213. The next prime is 51491263. The reversal of 51491232 is 23219415.

It can be written as a sum of positive squares in 4 ways, for example, as 48944016 + 2547216 = 6996^2 + 1596^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a junction number, because it is equal to n+sod(n) for n = 51491196 and 51491205.

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, 63244 + ... + 64052.

Almost surely, 2^51491232 is an apocalyptic number.

51491232 is a gapful number since it is divisible by the number (52) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51491232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83587140).

51491232 is an abundant number, since it is smaller than the sum of its proper divisors (115683048).

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

51491232 is a wasteful number, since it uses less digits than its factorization.

51491232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 855 (or 844 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 51491232 is about 7175.7391256929. The cubic root of 51491232 is about 372.0298276465.

The spelling of 51491232 in words is "fifty-one million, four hundred ninety-one thousand, two hundred thirty-two".