231640440 has 128 divisors (see below), whose sum is σ = 721474560. Its totient is φ = 59457024.

The previous prime is 231640439. The next prime is 231640471. The reversal of 231640440 is 44046132.

231640440 = T₄₄ + T₄₅ + ... + T₁₁₁₅.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 231640440.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 377574 + ... + 378186.

It is an arithmetic number, because the mean of its divisors is an integer number (5636520).

Almost surely, 2^231640440 is an apocalyptic number.

231640440 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 231640440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (360737280).

231640440 is an abundant number, since it is smaller than the sum of its proper divisors (489834120).

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

231640440 is a wasteful number, since it uses less digits than its factorization.

231640440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741 (or 737 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 231640440 is about 15219.7384997246. The cubic root of 231640440 is about 614.1457635801.

Adding to 231640440 its reverse (44046132), we get a palindrome (275686572).

The spelling of 231640440 in words is "two hundred thirty-one million, six hundred forty thousand, four hundred forty".