51143221 has 4 divisors (see below), whose sum is σ = 51469132. Its totient is φ = 50817312.

The previous prime is 51143201. The next prime is 51143233. The reversal of 51143221 is 12234115.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12234115 = 5 ⋅2446823.

It can be written as a sum of positive squares in 2 ways, for example, as 6320196 + 44823025 = 2514^2 + 6695^2 .

It is a cyclic number.

It is not a de Polignac number, because 51143221 - 2⁷ = 51143093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51143201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 162720 + ... + 163033.

It is an arithmetic number, because the mean of its divisors is an integer number (12867283).

Almost surely, 2^51143221 is an apocalyptic number.

It is an amenable number.

51143221 is a deficient number, since it is larger than the sum of its proper divisors (325911).

51143221 is a wasteful number, since it uses less digits than its factorization.

51143221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325910.

The product of its digits is 240, while the sum is 19.

The square root of 51143221 is about 7151.4488741793. The cubic root of 51143221 is about 371.1897930155.

Adding to 51143221 its reverse (12234115), we get a palindrome (63377336).

The spelling of 51143221 in words is "fifty-one million, one hundred forty-three thousand, two hundred twenty-one".