51686403021 has 48 divisors (see below), whose sum is σ = 84900204480. Its totient is φ = 31162475520.

The previous prime is 51686402987. The next prime is 51686403037. The reversal of 51686403021 is 12030468615.

It is a happy number.

51686403021 is a `hidden beast` number, since 5 + 1 + 6 + 8 + 640 + 3 + 0 + 2 + 1 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-51686403021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51686403121) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 465795 + ... + 565983.

It is an arithmetic number, because the mean of its divisors is an integer number (1768754260).

Almost surely, 2^51686403021 is an apocalyptic number.

It is an amenable number.

51686403021 is a deficient number, since it is larger than the sum of its proper divisors (33213801459).

51686403021 is a wasteful number, since it uses less digits than its factorization.

51686403021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100408 (or 100396 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 51686403021 in words is "fifty-one billion, six hundred eighty-six million, four hundred three thousand, twenty-one".