231020640 has 192 divisors, whose sum is σ = 824644800. Its totient is φ = 60383232.

The previous prime is 231020551. The next prime is 231020653. The reversal of 231020640 is 46020132.

It is a happy number.

231020640 is a `hidden beast` number, since 2 + 3 + 1 + 0 + 20 + 640 = 666.

It is a super-2 number, since 2×231020640² = 106741072212019200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 228456 + ... + 229464.

It is an arithmetic number, because the mean of its divisors is an integer number (4295025).

Almost surely, 2^231020640 is an apocalyptic number.

231020640 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 231020640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (412322400).

231020640 is an abundant number, since it is smaller than the sum of its proper divisors (593624160).

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

231020640 is a wasteful number, since it uses less digits than its factorization.

231020640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1086 (or 1072 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 231020640 is about 15199.3631445531. The cubic root of 231020640 is about 613.5975179899.

Adding to 231020640 its reverse (46020132), we get a palindrome (277040772).

The spelling of 231020640 in words is "two hundred thirty-one million, twenty thousand, six hundred forty".