51440000 has 80 divisors (see below), whose sum is σ = 128255820. Its totient is φ = 20544000.

The previous prime is 51439991. The next prime is 51440003. The reversal of 51440000 is 4415.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51440003) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 79679 + ... + 80321.

Almost surely, 2^51440000 is an apocalyptic number.

51440000 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 51440000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (64127910).

51440000 is an abundant number, since it is smaller than the sum of its proper divisors (76815820).

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

51440000 is an frugal number, since it uses more digits than its factorization.

51440000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 677 (or 650 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 14.

The square root of 51440000 is about 7172.1684308164. The cubic root of 51440000 is about 371.9064010864.

Adding to 51440000 its reverse (4415), we get a palindrome (51444415).

The spelling of 51440000 in words is "fifty-one million, four hundred forty thousand".