20408539 has 4 divisors (see below), whose sum is σ = 20474056. Its totient is φ = 20343024.

The previous prime is 20408533. The next prime is 20408543. The reversal of 20408539 is 93580402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93580402 = 2 ⋅46790201.

It is a cyclic number.

It is not a de Polignac number, because 20408539 - 2⁷ = 20408411 is a prime.

It is a super-2 number, since 2×20408539² = 833016928229042, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20408539.

It is not an unprimeable number, because it can be changed into a prime (20408533) 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, 32289 + ... + 32914.

It is an arithmetic number, because the mean of its divisors is an integer number (5118514).

Almost surely, 2^20408539 is an apocalyptic number.

20408539 is a deficient number, since it is larger than the sum of its proper divisors (65517).

20408539 is an equidigital number, since it uses as much as digits as its factorization.

20408539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65516.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 20408539 is about 4517.5811005448. The cubic root of 20408539 is about 273.2775603370.

The spelling of 20408539 in words is "twenty million, four hundred eight thousand, five hundred thirty-nine".