20409543 has 32 divisors (see below), whose sum is σ = 37701120. Its totient is φ = 10601280.

The previous prime is 20409539. The next prime is 20409547. The reversal of 20409543 is 34590402.

It is an interprime number because it is at equal distance from previous prime (20409539) and next prime (20409547).

It is not a de Polignac number, because 20409543 - 2² = 20409539 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20409547) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2830 + ... + 6987.

It is an arithmetic number, because the mean of its divisors is an integer number (1178160).

Almost surely, 2^20409543 is an apocalyptic number.

20409543 is a deficient number, since it is larger than the sum of its proper divisors (17291577).

20409543 is a wasteful number, since it uses less digits than its factorization.

20409543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9844 (or 9838 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 20409543 is about 4517.6922205923. The cubic root of 20409543 is about 273.2820415686.

Adding to 20409543 its reverse (34590402), we get a palindrome (54999945).

The spelling of 20409543 in words is "twenty million, four hundred nine thousand, five hundred forty-three".