20331240 has 32 divisors (see below), whose sum is σ = 60994080. Its totient is φ = 5421632.

The previous prime is 20331209. The next prime is 20331253. The reversal of 20331240 is 4213302.

It is a Harshad number since it is a multiple of its sum of digits (15).

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 7 ways as a sum of consecutive naturals, for example, 84594 + ... + 84833.

It is an arithmetic number, because the mean of its divisors is an integer number (1906065).

Almost surely, 2^20331240 is an apocalyptic number.

20331240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20331240 is an abundant number, since it is smaller than the sum of its proper divisors (40662840).

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

20331240 is a wasteful number, since it uses less digits than its factorization.

20331240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169441 (or 169437 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 20331240 is about 4509.0176313694. The cubic root of 20331240 is about 272.9321034979.

Adding to 20331240 its reverse (4213302), we get a palindrome (24544542).

The spelling of 20331240 in words is "twenty million, three hundred thirty-one thousand, two hundred forty".