51505661608 has 16 divisors (see below), whose sum is σ = 98395250580. Its totient is φ = 25266928128.

The previous prime is 51505661591. The next prime is 51505661621. The reversal of 51505661608 is 80616650515.

It can be written as a sum of positive squares in 2 ways, for example, as 49953144004 + 1552517604 = 223502^2 + 39402^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60737385 + ... + 60738232.

Almost surely, 2^51505661608 is an apocalyptic number.

It is an amenable number.

51505661608 is a deficient number, since it is larger than the sum of its proper divisors (46889588972).

51505661608 is a wasteful number, since it uses less digits than its factorization.

51505661608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121475676 (or 121475672 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 43.

The spelling of 51505661608 in words is "fifty-one billion, five hundred five million, six hundred sixty-one thousand, six hundred eight".