51665250 has 128 divisors (see below), whose sum is σ = 158925312. Its totient is φ = 10886400.

The previous prime is 51665219. The next prime is 51665279. The reversal of 51665250 is 5256615.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 67872 + ... + 68628.

It is an arithmetic number, because the mean of its divisors is an integer number (1241604).

Almost surely, 2^51665250 is an apocalyptic number.

51665250 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 51665250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (79462656).

51665250 is an abundant number, since it is smaller than the sum of its proper divisors (107260062).

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

51665250 is a wasteful number, since it uses less digits than its factorization.

51665250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 797 (or 787 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 51665250 is about 7187.8543390917. The cubic root of 51665250 is about 372.4484561505.

It can be divided in two parts, 51665 and 250, that added together give a palindrome (51915).

The spelling of 51665250 in words is "fifty-one million, six hundred sixty-five thousand, two hundred fifty".