51006647213 has 4 divisors (see below), whose sum is σ = 51048560220. Its totient is φ = 50964734208.

The previous prime is 51006647183. The next prime is 51006647249. The reversal of 51006647213 is 31274660015.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31274660015 = 5 ⋅6254932003.

It can be written as a sum of positive squares in 2 ways, for example, as 15774606409 + 35232040804 = 125597^2 + 187702^2 .

It is a cyclic number.

It is not a de Polignac number, because 51006647213 - 2¹² = 51006643117 is a prime.

It is a super-2 number, since 2×51006647213² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51006647513) 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, 20954678 + ... + 20957111.

It is an arithmetic number, because the mean of its divisors is an integer number (12762140055).

Almost surely, 2^51006647213 is an apocalyptic number.

It is an amenable number.

51006647213 is a deficient number, since it is larger than the sum of its proper divisors (41913007).

51006647213 is a wasteful number, since it uses less digits than its factorization.

51006647213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41913006.

The product of its (nonzero) digits is 30240, while the sum is 35.

The spelling of 51006647213 in words is "fifty-one billion, six million, six hundred forty-seven thousand, two hundred thirteen".