51732221 has 4 divisors (see below), whose sum is σ = 53981472. Its totient is φ = 49482972.

The previous prime is 51732169. The next prime is 51732223. The reversal of 51732221 is 12223715.

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 51732221 - 2¹⁴ = 51715837 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 2249227 = 51732221 / (5 + 1 + 7 + 3 + 2 + 2 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51732223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1124591 + ... + 1124636.

It is an arithmetic number, because the mean of its divisors is an integer number (13495368).

Almost surely, 2^51732221 is an apocalyptic number.

It is an amenable number.

51732221 is a deficient number, since it is larger than the sum of its proper divisors (2249251).

51732221 is a wasteful number, since it uses less digits than its factorization.

51732221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2249250.

The product of its digits is 840, while the sum is 23.

The square root of 51732221 is about 7192.5114528932. The cubic root of 51732221 is about 372.6093152435.

Adding to 51732221 its reverse (12223715), we get a palindrome (63955936).

The spelling of 51732221 in words is "fifty-one million, seven hundred thirty-two thousand, two hundred twenty-one".