851656639428 has 144 divisors (see below), whose sum is σ = 2486090880000. Its totient is φ = 240796018944.

The previous prime is 851656639417. The next prime is 851656639429. The reversal of 851656639428 is 824936656158.

It is a happy number.

851656639428 is a `hidden beast` number, since 8 + 5 + 16 + 566 + 39 + 4 + 28 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (851656639429) 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, 10058253 + ... + 10142571.

It is an arithmetic number, because the mean of its divisors is an integer number (17264520000).

Almost surely, 2^851656639428 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 851656639428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1243045440000).

851656639428 is an abundant number, since it is smaller than the sum of its proper divisors (1634434240572).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

851656639428 is a wasteful number, since it uses less digits than its factorization.

851656639428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84754 (or 84749 counting only the distinct ones).

The product of its digits is 74649600, while the sum is 63.

The spelling of 851656639428 in words is "eight hundred fifty-one billion, six hundred fifty-six million, six hundred thirty-nine thousand, four hundred twenty-eight".