28171181621 has 8 divisors (see below), whose sum is σ = 31386075264. Its totient is φ = 25065267520.

The previous prime is 28171181603. The next prime is 28171181639. The reversal of 28171181621 is 12618117182.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (28171181603) and next prime (28171181639).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28171181621 - 2²⁶ = 28104072757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28171181651) 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 7 ways as a sum of consecutive naturals, for example, 27244340 + ... + 27245373.

It is an arithmetic number, because the mean of its divisors is an integer number (3923259408).

Almost surely, 2^28171181621 is an apocalyptic number.

It is an amenable number.

28171181621 is a deficient number, since it is larger than the sum of its proper divisors (3214893643).

28171181621 is a wasteful number, since it uses less digits than its factorization.

28171181621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54489771.

The product of its digits is 10752, while the sum is 38.

The spelling of 28171181621 in words is "twenty-eight billion, one hundred seventy-one million, one hundred eighty-one thousand, six hundred twenty-one".