51398217522121 has 4 divisors (see below), whose sum is σ = 53170569850500. Its totient is φ = 49625865193744.

The previous prime is 51398217522103. The next prime is 51398217522137. The reversal of 51398217522121 is 12122571289315.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 32032373881225 + 19365843640896 = 5659715^2 + 4400664^2 .

It is a cyclic number.

It is not a de Polignac number, because 51398217522121 - 2¹⁹ = 51398216997833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51398217522101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 886176164146 + ... + 886176164203.

It is an arithmetic number, because the mean of its divisors is an integer number (13292642462625).

Almost surely, 2^{51398217522121} is an apocalyptic number.

It is an amenable number.

51398217522121 is a deficient number, since it is larger than the sum of its proper divisors (1772352328379).

51398217522121 is a wasteful number, since it uses less digits than its factorization.

51398217522121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1772352328378.

The product of its digits is 604800, while the sum is 49.

The spelling of 51398217522121 in words is "fifty-one trillion, three hundred ninety-eight billion, two hundred seventeen million, five hundred twenty-two thousand, one hundred twenty-one".