51000400 has 120 divisors (see below), whose sum is σ = 136446624. Its totient is φ = 18163200.

The previous prime is 51000379. The next prime is 51000413. The reversal of 51000400 is 400015.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

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, 294714 + ... + 294886.

Almost surely, 2^51000400 is an apocalyptic number.

51000400 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 51000400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68223312).

51000400 is an abundant number, since it is smaller than the sum of its proper divisors (85446224).

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

51000400 is a wasteful number, since it uses less digits than its factorization.

51000400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269 (or 258 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 51000400 is about 7141.4564340896. The cubic root of 51000400 is about 370.8439464482.

Adding to 51000400 its reverse (400015), we get a palindrome (51400415).

It can be divided in two parts, 5 and 1000400, that added together give a triangular number (1000405 = T₁₄₁₄).

The spelling of 51000400 in words is "fifty-one million, four hundred", and thus it is an aban number.