51206194909 has 4 divisors (see below), whose sum is σ = 52858007680. Its totient is φ = 49554382140.

The previous prime is 51206194901. The next prime is 51206194933. The reversal of 51206194909 is 90949160215.

It is a happy number.

51206194909 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, and also an emirpimes, since its reverse is a distinct semiprime: 90949160215 = 5 ⋅18189832043.

It is a cyclic number.

It is not a de Polignac number, because 51206194909 - 2³ = 51206194901 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 (51206194901) 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, 825906339 + ... + 825906400.

It is an arithmetic number, because the mean of its divisors is an integer number (13214501920).

Almost surely, 2^51206194909 is an apocalyptic number.

It is an amenable number.

51206194909 is a deficient number, since it is larger than the sum of its proper divisors (1651812771).

51206194909 is a wasteful number, since it uses less digits than its factorization.

51206194909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1651812770.

The product of its (nonzero) digits is 174960, while the sum is 46.

The spelling of 51206194909 in words is "fifty-one billion, two hundred six million, one hundred ninety-four thousand, nine hundred nine".