231121728 has 112 divisors (see below), whose sum is σ = 685312320. Its totient is φ = 76377600.

The previous prime is 231121727. The next prime is 231121753. The reversal of 231121728 is 827121132.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231121727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 225858 + ... + 226878.

It is an arithmetic number, because the mean of its divisors is an integer number (6118860).

Almost surely, 2^231121728 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 231121728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (342656160).

231121728 is an abundant number, since it is smaller than the sum of its proper divisors (454190592).

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

231121728 is a wasteful number, since it uses less digits than its factorization.

231121728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1173 (or 1157 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 231121728 is about 15202.6881833444. The cubic root of 231121728 is about 613.6870024922.

The spelling of 231121728 in words is "two hundred thirty-one million, one hundred twenty-one thousand, seven hundred twenty-eight".