51666919636 has 6 divisors (see below), whose sum is σ = 90417109370. Its totient is φ = 25833459816.

The previous prime is 51666919631. The next prime is 51666919649. The reversal of 51666919636 is 63691966615.

It can be written as a sum of positive squares in only one way, i.e., 47428128400 + 4238791236 = 217780^2 + 65106^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51666919631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6458364951 + ... + 6458364958.

Almost surely, 2^51666919636 is an apocalyptic number.

It is an amenable number.

51666919636 is a deficient number, since it is larger than the sum of its proper divisors (38750189734).

51666919636 is a wasteful number, since it uses less digits than its factorization.

51666919636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12916729913 (or 12916729911 counting only the distinct ones).

The product of its digits is 9447840, while the sum is 58.

The spelling of 51666919636 in words is "fifty-one billion, six hundred sixty-six million, nine hundred nineteen thousand, six hundred thirty-six".