51215544 has 64 divisors (see below), whose sum is σ = 143462400. Its totient is φ = 16928352.

The previous prime is 51215501. The next prime is 51215551. The reversal of 51215544 is 44551215.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26499 + ... + 28365.

It is an arithmetic number, because the mean of its divisors is an integer number (2241600).

Almost surely, 2^51215544 is an apocalyptic number.

51215544 is a gapful number since it is divisible by the number (54) 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 51215544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (71731200).

51215544 is an abundant number, since it is smaller than the sum of its proper divisors (92246856).

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

51215544 is a wasteful number, since it uses less digits than its factorization.

51215544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2009 (or 1999 counting only the distinct ones).

The product of its digits is 4000, while the sum is 27.

The square root of 51215544 is about 7156.5036155933. The cubic root of 51215544 is about 371.3646804165.

Adding to 51215544 its reverse (44551215), we get a palindrome (95766759).

The spelling of 51215544 in words is "fifty-one million, two hundred fifteen thousand, five hundred forty-four".