51978617 has 2 divisors, whose sum is σ = 51978618. Its totient is φ = 51978616.

The previous prime is 51978559. The next prime is 51978629. The reversal of 51978617 is 71687915.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49716601 + 2262016 = 7051^2 + 1504^2 .

It is a cyclic number.

It is not a de Polignac number, because 51978617 - 2²⁰ = 50930041 is a prime.

It is a super-3 number, since 3×51978617³ (a number of 24 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (51978677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25989308 + 25989309.

It is an arithmetic number, because the mean of its divisors is an integer number (25989309).

Almost surely, 2^51978617 is an apocalyptic number.

It is an amenable number.

51978617 is a deficient number, since it is larger than the sum of its proper divisors (1).

51978617 is an equidigital number, since it uses as much as digits as its factorization.

51978617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 105840, while the sum is 44.

The square root of 51978617 is about 7209.6197541895. The cubic root of 51978617 is about 373.1999469455.

The spelling of 51978617 in words is "fifty-one million, nine hundred seventy-eight thousand, six hundred seventeen".