51991707 has 18 divisors (see below), whose sum is σ = 72869916. Its totient is φ = 32970960.

The previous prime is 51991663. The next prime is 51991711. The reversal of 51991707 is 70719915.

51991707 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 51991707 - 2⁸ = 51991451 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51991727) 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 17 ways as a sum of consecutive naturals, for example, 287157 + ... + 287337.

Almost surely, 2^51991707 is an apocalyptic number.

51991707 is a deficient number, since it is larger than the sum of its proper divisors (20878209).

51991707 is an equidigital number, since it uses as much as digits as its factorization.

51991707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 411 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 19845, while the sum is 39.

The square root of 51991707 is about 7210.5275119092. The cubic root of 51991707 is about 373.2312725018.

The spelling of 51991707 in words is "fifty-one million, nine hundred ninety-one thousand, seven hundred seven".