51649798549 has 4 divisors (see below), whose sum is σ = 52496516620. Its totient is φ = 50803080480.

The previous prime is 51649798517. The next prime is 51649798583. The reversal of 51649798549 is 94589794615.

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 17419248324 + 34230550225 = 131982^2 + 185015^2 .

It is a cyclic number.

It is not a de Polignac number, because 51649798549 - 2⁵ = 51649798517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51649798649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 423358944 + ... + 423359065.

It is an arithmetic number, because the mean of its divisors is an integer number (13124129155).

Almost surely, 2^51649798549 is an apocalyptic number.

It is an amenable number.

51649798549 is a deficient number, since it is larger than the sum of its proper divisors (846718071).

51649798549 is an equidigital number, since it uses as much as digits as its factorization.

51649798549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 846718070.

The product of its digits is 97977600, while the sum is 67.

The spelling of 51649798549 in words is "fifty-one billion, six hundred forty-nine million, seven hundred ninety-eight thousand, five hundred forty-nine".