28221631618687 has 16 divisors (see below), whose sum is σ = 30892196397888. Its totient is φ = 25622487866880.

The previous prime is 28221631618669. The next prime is 28221631618771. The reversal of 28221631618687 is 78681613612282.

It is a cyclic number.

It is not a de Polignac number, because 28221631618687 - 2³⁹ = 27671875804799 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (61).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28221631618657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16523463 + ... + 18151255.

It is an arithmetic number, because the mean of its divisors is an integer number (1930762274868).

Almost surely, 2^{28221631618687} is an apocalyptic number.

28221631618687 is a deficient number, since it is larger than the sum of its proper divisors (2670564779201).

28221631618687 is a wasteful number, since it uses less digits than its factorization.

28221631618687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1649730.

The product of its digits is 18579456, while the sum is 61.

The spelling of 28221631618687 in words is "twenty-eight trillion, two hundred twenty-one billion, six hundred thirty-one million, six hundred eighteen thousand, six hundred eighty-seven".