231281820 has 432 divisors, whose sum is σ = 927186624. Its totient is φ = 45619200.

The previous prime is 231281773. The next prime is 231281839. The reversal of 231281820 is 28182132.

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 143 ways as a sum of consecutive naturals, for example, 5641000 + ... + 5641040.

Almost surely, 2^231281820 is an apocalyptic number.

231281820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231281820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (463593312).

231281820 is an abundant number, since it is smaller than the sum of its proper divisors (695904804).

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

231281820 is a wasteful number, since it uses less digits than its factorization.

231281820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 106 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 231281820 is about 15207.9525249127. The cubic root of 231281820 is about 613.8286647884.

The spelling of 231281820 in words is "two hundred thirty-one million, two hundred eighty-one thousand, eight hundred twenty".