51216953209 has 8 divisors (see below), whose sum is σ = 51650137800. Its totient is φ = 50784961536.

The previous prime is 51216953191. The next prime is 51216953213. The reversal of 51216953209 is 90235961215.

It can be written as a sum of positive squares in 4 ways, for example, as 4042416400 + 47174536809 = 63580^2 + 217197^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51216953209 - 2²¹ = 51214856057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51216953239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 211894 + ... + 383839.

It is an arithmetic number, because the mean of its divisors is an integer number (6456267225).

Almost surely, 2^51216953209 is an apocalyptic number.

It is an amenable number.

51216953209 is a deficient number, since it is larger than the sum of its proper divisors (433184591).

51216953209 is a wasteful number, since it uses less digits than its factorization.

51216953209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596459.

The product of its (nonzero) digits is 145800, while the sum is 43.

The spelling of 51216953209 in words is "fifty-one billion, two hundred sixteen million, nine hundred fifty-three thousand, two hundred nine".