51553221 has 4 divisors (see below), whose sum is σ = 68737632. Its totient is φ = 34368812.

The previous prime is 51553211. The next prime is 51553283. The reversal of 51553221 is 12235515.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 51553221 - 2⁶ = 51553157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 51553191 and 51553200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51553211) 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, 8592201 + ... + 8592206.

It is an arithmetic number, because the mean of its divisors is an integer number (17184408).

Almost surely, 2^51553221 is an apocalyptic number.

It is an amenable number.

51553221 is a deficient number, since it is larger than the sum of its proper divisors (17184411).

51553221 is a wasteful number, since it uses less digits than its factorization.

51553221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17184410.

The product of its digits is 1500, while the sum is 24.

The square root of 51553221 is about 7180.0571724743. The cubic root of 51553221 is about 372.1790602296.

Adding to 51553221 its reverse (12235515), we get a palindrome (63788736).

The spelling of 51553221 in words is "fifty-one million, five hundred fifty-three thousand, two hundred twenty-one".