51421221 has 12 divisors (see below), whose sum is σ = 75011820. Its totient is φ = 33940800.

The previous prime is 51421217. The next prime is 51421229. The reversal of 51421221 is 12212415.

It can be written as a sum of positive squares in 2 ways, for example, as 49702500 + 1718721 = 7050^2 + 1311^2 .

It is not a de Polignac number, because 51421221 - 2² = 51421217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 51421194 and 51421203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51421229) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27376 + ... + 29193.

It is an arithmetic number, because the mean of its divisors is an integer number (6250985).

Almost surely, 2^51421221 is an apocalyptic number.

It is an amenable number.

51421221 is a deficient number, since it is larger than the sum of its proper divisors (23590599).

51421221 is a wasteful number, since it uses less digits than its factorization.

51421221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56676 (or 56673 counting only the distinct ones).

The product of its digits is 160, while the sum is 18.

The square root of 51421221 is about 7170.8591535464. The cubic root of 51421221 is about 371.8611387720.

Adding to 51421221 its reverse (12212415), we get a palindrome (63633636).

The spelling of 51421221 in words is "fifty-one million, four hundred twenty-one thousand, two hundred twenty-one".