51705691 has 4 divisors (see below), whose sum is σ = 52207792. Its totient is φ = 51203592.

The previous prime is 51705683. The next prime is 51705701. The reversal of 51705691 is 19650715.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51705691 - 2³ = 51705683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51705601) 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, 250896 + ... + 251101.

It is an arithmetic number, because the mean of its divisors is an integer number (13051948).

Almost surely, 2^51705691 is an apocalyptic number.

51705691 is a deficient number, since it is larger than the sum of its proper divisors (502101).

51705691 is a wasteful number, since it uses less digits than its factorization.

51705691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 502100.

The product of its (nonzero) digits is 9450, while the sum is 34.

The square root of 51705691 is about 7190.6669370789. Note that the first 3 decimals coincide. The cubic root of 51705691 is about 372.5456088772.

The spelling of 51705691 in words is "fifty-one million, seven hundred five thousand, six hundred ninety-one".