51444221 has 4 divisors (see below), whose sum is σ = 53103744. Its totient is φ = 49784700.

The previous prime is 51444199. The next prime is 51444223. The reversal of 51444221 is 12244415.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12244415 = 5 ⋅2448883.

It is a cyclic number.

It is not a de Polignac number, because 51444221 - 2⁶ = 51444157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51444223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 829715 + ... + 829776.

It is an arithmetic number, because the mean of its divisors is an integer number (13275936).

Almost surely, 2^51444221 is an apocalyptic number.

It is an amenable number.

51444221 is a deficient number, since it is larger than the sum of its proper divisors (1659523).

51444221 is a wasteful number, since it uses less digits than its factorization.

51444221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1659522.

The product of its digits is 1280, while the sum is 23.

The square root of 51444221 is about 7172.4626872505. The cubic root of 51444221 is about 371.9165732869.

Adding to 51444221 its reverse (12244415), we get a palindrome (63688636).

The spelling of 51444221 in words is "fifty-one million, four hundred forty-four thousand, two hundred twenty-one".