51717661 has 4 divisors (see below), whose sum is σ = 51796800. Its totient is φ = 51638524.

The previous prime is 51717649. The next prime is 51717683. The reversal of 51717661 is 16671715.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51717661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51717461) 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, 38581 + ... + 39898.

It is an arithmetic number, because the mean of its divisors is an integer number (12949200).

Almost surely, 2^51717661 is an apocalyptic number.

It is an amenable number.

51717661 is a deficient number, since it is larger than the sum of its proper divisors (79139).

51717661 is an equidigital number, since it uses as much as digits as its factorization.

51717661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79138.

The product of its digits is 8820, while the sum is 34.

The square root of 51717661 is about 7191.4992178266. The cubic root of 51717661 is about 372.5743550802.

The spelling of 51717661 in words is "fifty-one million, seven hundred seventeen thousand, six hundred sixty-one".