51991371 has 24 divisors (see below), whose sum is σ = 77901824. Its totient is φ = 33378480.

The previous prime is 51991369. The next prime is 51991439. The reversal of 51991371 is 17319915.

51991371 is a `hidden beast` number, since 519 + 9 + 137 + 1 = 666.

51991371 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 51991371 - 2¹ = 51991369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51991301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 85350 + ... + 85956.

Almost surely, 2^51991371 is an apocalyptic number.

51991371 is a deficient number, since it is larger than the sum of its proper divisors (25910453).

51991371 is a wasteful number, since it uses less digits than its factorization.

51991371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 951 (or 948 counting only the distinct ones).

The product of its digits is 8505, while the sum is 36.

The square root of 51991371 is about 7210.5042126054. The cubic root of 51991371 is about 373.2304684891.

The spelling of 51991371 in words is "fifty-one million, nine hundred ninety-one thousand, three hundred seventy-one".