51291500 has 72 divisors (see below), whose sum is σ = 121500288. Its totient is φ = 18907200.

The previous prime is 51291497. The next prime is 51291503. The reversal of 51291500 is 519215.

51291500 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (51291497) and next prime (51291503).

It is not an unprimeable number, because it can be changed into a prime (51291503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 84197 + ... + 84803.

It is an arithmetic number, because the mean of its divisors is an integer number (1687504).

Almost surely, 2^51291500 is an apocalyptic number.

51291500 is a gapful number since it is divisible by the number (50) 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 51291500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (60750144).

51291500 is an abundant number, since it is smaller than the sum of its proper divisors (70208788).

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

51291500 is a wasteful number, since it uses less digits than its factorization.

51291500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652 (or 627 counting only the distinct ones).

The product of its (nonzero) digits is 450, while the sum is 23.

The square root of 51291500 is about 7161.8084308364. The cubic root of 51291500 is about 371.5481757676.

The spelling of 51291500 in words is "fifty-one million, two hundred ninety-one thousand, five hundred".