51531500 has 48 divisors (see below), whose sum is σ = 117464256. Its totient is φ = 19712000.

The previous prime is 51531451. The next prime is 51531511. The reversal of 51531500 is 513515.

It is a happy number.

51531500 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 9260 + ... + 13740.

It is an arithmetic number, because the mean of its divisors is an integer number (2447172).

Almost surely, 2^51531500 is an apocalyptic number.

51531500 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 51531500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (58732128).

51531500 is an abundant number, since it is smaller than the sum of its proper divisors (65932756).

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

51531500 is a wasteful number, since it uses less digits than its factorization.

51531500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4523 (or 4511 counting only the distinct ones).

The product of its (nonzero) digits is 375, while the sum is 20.

The square root of 51531500 is about 7178.5444207026. The cubic root of 51531500 is about 372.1267826231.

The spelling of 51531500 in words is "fifty-one million, five hundred thirty-one thousand, five hundred".