20505340 has 12 divisors (see below), whose sum is σ = 43061256. Its totient is φ = 8202128.

The previous prime is 20505307. The next prime is 20505341. The reversal of 20505340 is 4350502.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20505341) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 512614 + ... + 512653.

It is an arithmetic number, because the mean of its divisors is an integer number (3588438).

Almost surely, 2^20505340 is an apocalyptic number.

20505340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20505340 is an abundant number, since it is smaller than the sum of its proper divisors (22555916).

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

20505340 is a wasteful number, since it uses less digits than its factorization.

20505340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1025276 (or 1025274 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 19.

The square root of 20505340 is about 4528.2822350203. The cubic root of 20505340 is about 273.7089455611.

Adding to 20505340 its reverse (4350502), we get a palindrome (24855842).

The spelling of 20505340 in words is "twenty million, five hundred five thousand, three hundred forty".