51221744 has 40 divisors (see below), whose sum is σ = 115572960. Its totient is φ = 21535488.

The previous prime is 51221741. The next prime is 51221771. The reversal of 51221744 is 44712215.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51221741) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1622 + ... + 10250.

It is an arithmetic number, because the mean of its divisors is an integer number (2889324).

Almost surely, 2^51221744 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51221744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (57786480).

51221744 is an abundant number, since it is smaller than the sum of its proper divisors (64351216).

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

51221744 is a wasteful number, since it uses less digits than its factorization.

51221744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8697 (or 8691 counting only the distinct ones).

The product of its digits is 2240, while the sum is 26.

The square root of 51221744 is about 7156.9367749059. The cubic root of 51221744 is about 371.3796652429.

Adding to 51221744 its reverse (44712215), we get a palindrome (95933959).

The spelling of 51221744 in words is "fifty-one million, two hundred twenty-one thousand, seven hundred forty-four".