51217123513 has 8 divisors (see below), whose sum is σ = 52205845248. Its totient is φ = 50229230064.

The previous prime is 51217123483. The next prime is 51217123537. The reversal of 51217123513 is 31532171215.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51217123513 is a prime.

It is a super-2 number, since 2×51217123513² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51217123543) 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, 81481 + ... + 330262.

It is an arithmetic number, because the mean of its divisors is an integer number (6525730656).

Almost surely, 2^51217123513 is an apocalyptic number.

51217123513 is a gapful number since it is divisible by the number (53) formed by its first and last digit.

It is an amenable number.

51217123513 is a deficient number, since it is larger than the sum of its proper divisors (988721735).

51217123513 is a wasteful number, since it uses less digits than its factorization.

51217123513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414143.

The product of its digits is 6300, while the sum is 31.

Adding to 51217123513 its reverse (31532171215), we get a palindrome (82749294728).

The spelling of 51217123513 in words is "fifty-one billion, two hundred seventeen million, one hundred twenty-three thousand, five hundred thirteen".