51498198781 has 2 divisors, whose sum is σ = 51498198782. Its totient is φ = 51498198780.

The previous prime is 51498198769. The next prime is 51498198827. The reversal of 51498198781 is 18789189415.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34471863556 + 17026335225 = 185666^2 + 130485^2 .

It is a cyclic number.

It is not a de Polignac number, because 51498198781 - 2²⁵ = 51464644349 is a prime.

It is a super-2 number, since 2×51498198781² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51498198761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25749099390 + 25749099391.

It is an arithmetic number, because the mean of its divisors is an integer number (25749099391).

Almost surely, 2^51498198781 is an apocalyptic number.

It is an amenable number.

51498198781 is a deficient number, since it is larger than the sum of its proper divisors (1).

51498198781 is an equidigital number, since it uses as much as digits as its factorization.

51498198781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5806080, while the sum is 61.

The spelling of 51498198781 in words is "fifty-one billion, four hundred ninety-eight million, one hundred ninety-eight thousand, seven hundred eighty-one".