51707821 has 8 divisors (see below), whose sum is σ = 56510784. Its totient is φ = 46921920.

The previous prime is 51707819. The next prime is 51707869. The reversal of 51707821 is 12870715.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51707821 - 2¹ = 51707819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51707891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2560 + ... + 10486.

It is an arithmetic number, because the mean of its divisors is an integer number (7063848).

Almost surely, 2^51707821 is an apocalyptic number.

It is an amenable number.

51707821 is a deficient number, since it is larger than the sum of its proper divisors (4802963).

51707821 is a wasteful number, since it uses less digits than its factorization.

51707821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8531.

The product of its (nonzero) digits is 3920, while the sum is 31.

The square root of 51707821 is about 7190.8150442074. The cubic root of 51707821 is about 372.5507244408.

The spelling of 51707821 in words is "fifty-one million, seven hundred seven thousand, eight hundred twenty-one".