28257161638 has 16 divisors (see below), whose sum is σ = 43670749536. Its totient is φ = 13706591040.

The previous prime is 28257161593. The next prime is 28257161641. The reversal of 28257161638 is 83616175282.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 28257161591 and 28257161600.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1577506 + ... + 1595317.

It is an arithmetic number, because the mean of its divisors is an integer number (2729421846).

Almost surely, 2^28257161638 is an apocalyptic number.

28257161638 is a deficient number, since it is larger than the sum of its proper divisors (15413587898).

28257161638 is a wasteful number, since it uses less digits than its factorization.

28257161638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3172959.

The product of its digits is 967680, while the sum is 49.

The spelling of 28257161638 in words is "twenty-eight billion, two hundred fifty-seven million, one hundred sixty-one thousand, six hundred thirty-eight".