51798821 has 4 divisors (see below), whose sum is σ = 52648044. Its totient is φ = 50949600.

The previous prime is 51798809. The next prime is 51798833. The reversal of 51798821 is 12889715.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12889715 = 5 ⋅2577943.

It is an interprime number because it is at equal distance from previous prime (51798809) and next prime (51798833).

It can be written as a sum of positive squares in 2 ways, for example, as 12285025 + 39513796 = 3505^2 + 6286^2 .

It is a cyclic number.

It is not a de Polignac number, because 51798821 - 2²² = 47604517 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 (51792821) 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, 424520 + ... + 424641.

It is an arithmetic number, because the mean of its divisors is an integer number (13162011).

Almost surely, 2^51798821 is an apocalyptic number.

It is an amenable number.

51798821 is a deficient number, since it is larger than the sum of its proper divisors (849223).

51798821 is an equidigital number, since it uses as much as digits as its factorization.

51798821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849222.

The product of its digits is 40320, while the sum is 41.

The square root of 51798821 is about 7197.1397791067. The cubic root of 51798821 is about 372.7691456049.

The spelling of 51798821 in words is "fifty-one million, seven hundred ninety-eight thousand, eight hundred twenty-one".