20305540 has 12 divisors (see below), whose sum is σ = 42641676. Its totient is φ = 8122208.

The previous prime is 20305517. The next prime is 20305541. The reversal of 20305540 is 4550302.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2715904 + 17589636 = 1648^2 + 4194^2 .

It is not an unprimeable number, because it can be changed into a prime (20305541) 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, 507619 + ... + 507658.

It is an arithmetic number, because the mean of its divisors is an integer number (3553473).

Almost surely, 2^20305540 is an apocalyptic number.

20305540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20305540 is an abundant number, since it is smaller than the sum of its proper divisors (22336136).

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

20305540 is a wasteful number, since it uses less digits than its factorization.

20305540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1015286 (or 1015284 counting only the distinct ones).

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

The square root of 20305540 is about 4506.1668855026. The cubic root of 20305540 is about 272.8170537408.

Adding to 20305540 its reverse (4550302), we get a palindrome (24855842).

The spelling of 20305540 in words is "twenty million, three hundred five thousand, five hundred forty".