51661357907 has 4 divisors (see below), whose sum is σ = 51851990496. Its totient is φ = 51470725320.

The previous prime is 51661357897. The next prime is 51661357933. The reversal of 51661357907 is 70975316615.

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 51661357907 - 2¹² = 51661353811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51661357607) 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, 95315888 + ... + 95316429.

It is an arithmetic number, because the mean of its divisors is an integer number (12962997624).

Almost surely, 2^51661357907 is an apocalyptic number.

51661357907 is a deficient number, since it is larger than the sum of its proper divisors (190632589).

51661357907 is a wasteful number, since it uses less digits than its factorization.

51661357907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190632588.

The product of its (nonzero) digits is 1190700, while the sum is 50.

The spelling of 51661357907 in words is "fifty-one billion, six hundred sixty-one million, three hundred fifty-seven thousand, nine hundred seven".