20131240 has 32 divisors (see below), whose sum is σ = 45434880. Its totient is φ = 8027712.

The previous prime is 20131229. The next prime is 20131259. The reversal of 20131240 is 4213102.

It is a self number, because there is not a number n which added to its sum of digits gives 20131240.

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, 17977 + ... + 19063.

It is an arithmetic number, because the mean of its divisors is an integer number (1419840).

Almost surely, 2^20131240 is an apocalyptic number.

20131240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20131240 is an abundant number, since it is smaller than the sum of its proper divisors (25303640).

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

20131240 is a wasteful number, since it uses less digits than its factorization.

20131240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1561 (or 1557 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 20131240 is about 4486.7850405385. The cubic root of 20131240 is about 272.0342012933.

Adding to 20131240 its reverse (4213102), we get a palindrome (24344342).

The spelling of 20131240 in words is "twenty million, one hundred thirty-one thousand, two hundred forty".