51205621 has 8 divisors (see below), whose sum is σ = 52512320. Its totient is φ = 49915008.

The previous prime is 51205603. The next prime is 51205633. The reversal of 51205621 is 12650215.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51205621 - 2⁷ = 51205493 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51205592 and 51205601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51205601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2560 + ... + 10438.

It is an arithmetic number, because the mean of its divisors is an integer number (6564040).

Almost surely, 2^51205621 is an apocalyptic number.

It is an amenable number.

51205621 is a deficient number, since it is larger than the sum of its proper divisors (1306699).

51205621 is an equidigital number, since it uses as much as digits as its factorization.

51205621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8043.

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 51205621 is about 7155.8102965353. The cubic root of 51205621 is about 371.3406949266.

Adding to 51205621 its reverse (12650215), we get a palindrome (63855836).

The spelling of 51205621 in words is "fifty-one million, two hundred five thousand, six hundred twenty-one".