1231640 has 32 divisors (see below), whose sum is σ = 2842560. Its totient is φ = 480000.

The previous prime is 1231631. The next prime is 1231663. The reversal of 1231640 is 461321.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1265 + ... + 2015.

It is an arithmetic number, because the mean of its divisors is an integer number (88830).

2^1231640 is an apocalyptic number.

1231640 is a gapful number since it is divisible by the number (10) 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 1231640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1421280).

1231640 is an abundant number, since it is smaller than the sum of its proper divisors (1610920).

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

1231640 is a wasteful number, since it uses less digits than its factorization.

1231640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 803 (or 799 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1231640 is about 1109.7927734492. The cubic root of 1231640 is about 107.1917254325.

Adding to 1231640 its reverse (461321), we get a palindrome (1692961).

The spelling of 1231640 in words is "one million, two hundred thirty-one thousand, six hundred forty".