51871820 has 96 divisors (see below), whose sum is σ = 146313216. Its totient is φ = 14918400.

The previous prime is 51871769. The next prime is 51871823. The reversal of 51871820 is 2817815.

It is a happy number.

It is a super-2 number, since 2×51871820² = 5381371420224800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51871823) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18725 + ... + 21315.

It is an arithmetic number, because the mean of its divisors is an integer number (1524096).

Almost surely, 2^51871820 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51871820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73156608).

51871820 is an abundant number, since it is smaller than the sum of its proper divisors (94441396).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51871820 is a wasteful number, since it uses less digits than its factorization.

51871820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2631 (or 2629 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 51871820 is about 7202.2093832379. The cubic root of 51871820 is about 372.9441753407.

It can be divided in two parts, 5187 and 1820, that added together give a palindrome (7007).

The spelling of 51871820 in words is "fifty-one million, eight hundred seventy-one thousand, eight hundred twenty".