51550821 has 24 divisors (see below), whose sum is σ = 86711040. Its totient is φ = 28899936.

The previous prime is 51550813. The next prime is 51550853. The reversal of 51550821 is 12805515.

It is not a de Polignac number, because 51550821 - 2³ = 51550813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51550801) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4381 + ... + 11058.

It is an arithmetic number, because the mean of its divisors is an integer number (3612960).

Almost surely, 2^51550821 is an apocalyptic number.

It is an amenable number.

51550821 is a deficient number, since it is larger than the sum of its proper divisors (35160219).

51550821 is a wasteful number, since it uses less digits than its factorization.

51550821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15505 (or 15502 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 27.

The square root of 51550821 is about 7179.8900409407. The cubic root of 51550821 is about 372.1732846861.

The spelling of 51550821 in words is "fifty-one million, five hundred fifty thousand, eight hundred twenty-one".