20613540 has 24 divisors (see below), whose sum is σ = 57718080. Its totient is φ = 5496928.

The previous prime is 20613533. The next prime is 20613563. The reversal of 20613540 is 4531602.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 171720 + ... + 171839.

It is an arithmetic number, because the mean of its divisors is an integer number (2404920).

Almost surely, 2^20613540 is an apocalyptic number.

20613540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20613540 is an abundant number, since it is smaller than the sum of its proper divisors (37104540).

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

20613540 is a wasteful number, since it uses less digits than its factorization.

20613540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343571 (or 343569 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 20613540 is about 4540.2136513605. The cubic root of 20613540 is about 274.1895255785.

The spelling of 20613540 in words is "twenty million, six hundred thirteen thousand, five hundred forty".