51930221 has 4 divisors (see below), whose sum is σ = 59348832. Its totient is φ = 44511612.

The previous prime is 51930209. The next prime is 51930289. The reversal of 51930221 is 12203915.

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 51930221 - 2⁶ = 51930157 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 (51930421) 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, 3709295 + ... + 3709308.

It is an arithmetic number, because the mean of its divisors is an integer number (14837208).

Almost surely, 2^51930221 is an apocalyptic number.

It is an amenable number.

51930221 is a deficient number, since it is larger than the sum of its proper divisors (7418611).

51930221 is an equidigital number, since it uses as much as digits as its factorization.

51930221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7418610.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 51930221 is about 7206.2626235796. The cubic root of 51930221 is about 373.0840852439.

The spelling of 51930221 in words is "fifty-one million, nine hundred thirty thousand, two hundred twenty-one".