51642578421 has 12 divisors (see below), whose sum is σ = 85251240672. Its totient is φ = 29510044776.

The previous prime is 51642578411. The next prime is 51642578441. The reversal of 51642578421 is 12487524615.

51642578421 is a `hidden beast` number, since 5 + 16 + 42 + 578 + 4 + 21 = 666.

It is not a de Polignac number, because 51642578421 - 2¹⁰ = 51642577397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51642578411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 409861671 + ... + 409861796.

It is an arithmetic number, because the mean of its divisors is an integer number (7104270056).

Almost surely, 2^51642578421 is an apocalyptic number.

It is an amenable number.

51642578421 is a deficient number, since it is larger than the sum of its proper divisors (33608662251).

51642578421 is a wasteful number, since it uses less digits than its factorization.

51642578421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 819723480 (or 819723477 counting only the distinct ones).

The product of its digits is 537600, while the sum is 45.

The spelling of 51642578421 in words is "fifty-one billion, six hundred forty-two million, five hundred seventy-eight thousand, four hundred twenty-one".