51971868 has 96 divisors (see below), whose sum is σ = 147219520. Its totient is φ = 15956352.

The previous prime is 51971863. The next prime is 51971869. The reversal of 51971868 is 86817915.

51971868 is a `hidden beast` number, since 519 + 71 + 8 + 68 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51971863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 113496 + ... + 113952.

Almost surely, 2^51971868 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 51971868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73609760).

51971868 is an abundant number, since it is smaller than the sum of its proper divisors (95247652).

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

51971868 is a wasteful number, since it uses less digits than its factorization.

51971868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495 (or 475 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The square root of 51971868 is about 7209.1516837975. The cubic root of 51971868 is about 373.1837939220.

The spelling of 51971868 in words is "fifty-one million, nine hundred seventy-one thousand, eight hundred sixty-eight".