51681620613 has 8 divisors (see below), whose sum is σ = 78752945728. Its totient is φ = 29532354624.

The previous prime is 51681620611. The next prime is 51681620693. The reversal of 51681620613 is 31602618615.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51681620613 - 2¹ = 51681620611 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51681620611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1230514756 + ... + 1230514797.

It is an arithmetic number, because the mean of its divisors is an integer number (9844118216).

Almost surely, 2^51681620613 is an apocalyptic number.

It is an amenable number.

51681620613 is a deficient number, since it is larger than the sum of its proper divisors (27071325115).

51681620613 is a wasteful number, since it uses less digits than its factorization.

51681620613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2461029563.

The product of its (nonzero) digits is 51840, while the sum is 39.

The spelling of 51681620613 in words is "fifty-one billion, six hundred eighty-one million, six hundred twenty thousand, six hundred thirteen".