28981317121 has 3 divisors (see below), whose sum is σ = 28981487361. Its totient is φ = 28981146882.

The previous prime is 28981317119. The next prime is 28981317163. The reversal of 28981317121 is 12171318982.

The square root of 28981317121 is 170239.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 28981317121 - 2¹ = 28981317119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28981317721) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 85120 + ... + 255358.

It is an arithmetic number, because the mean of its divisors is an integer number (9660495787).

Almost surely, 2^28981317121 is an apocalyptic number.

28981317121 is the 170239-th square number.

28981317121 is the 85120-th centered octagonal number.

It is an amenable number.

28981317121 is a deficient number, since it is larger than the sum of its proper divisors (170240).

28981317121 is an frugal number, since it uses more digits than its factorization.

28981317121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340478 (or 170239 counting only the distinct ones).

The product of its digits is 48384, while the sum is 43.

The spelling of 28981317121 in words is "twenty-eight billion, nine hundred eighty-one million, three hundred seventeen thousand, one hundred twenty-one".