51661755961 has 4 divisors (see below), whose sum is σ = 51737396112. Its totient is φ = 51586115812.

The previous prime is 51661755947. The next prime is 51661755983. The reversal of 51661755961 is 16955716615.

51661755961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 not a de Polignac number, because 51661755961 - 2¹⁹ = 51661231673 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51661755899 and 51661755908.

It is not an unprimeable number, because it can be changed into a prime (51661755931) 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, 37819051 + ... + 37820416.

It is an arithmetic number, because the mean of its divisors is an integer number (12934349028).

Almost surely, 2^51661755961 is an apocalyptic number.

It is an amenable number.

51661755961 is a deficient number, since it is larger than the sum of its proper divisors (75640151).

51661755961 is an equidigital number, since it uses as much as digits as its factorization.

51661755961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75640150.

The product of its digits is 1701000, while the sum is 52.

The spelling of 51661755961 in words is "fifty-one billion, six hundred sixty-one million, seven hundred fifty-five thousand, nine hundred sixty-one".