20618413 has 4 divisors (see below), whose sum is σ = 20638908. Its totient is φ = 20597920.

The previous prime is 20618407. The next prime is 20618453. The reversal of 20618413 is 31481602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31481602 = 2 ⋅15740801.

It can be written as a sum of positive squares in 2 ways, for example, as 6980164 + 13638249 = 2642^2 + 3693^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20618413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20618453) 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, 8656 + ... + 10777.

It is an arithmetic number, because the mean of its divisors is an integer number (5159727).

Almost surely, 2^20618413 is an apocalyptic number.

It is an amenable number.

20618413 is a deficient number, since it is larger than the sum of its proper divisors (20495).

20618413 is a wasteful number, since it uses less digits than its factorization.

20618413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20494.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 20618413 is about 4540.7502684028. The cubic root of 20618413 is about 274.2111298297.

The spelling of 20618413 in words is "twenty million, six hundred eighteen thousand, four hundred thirteen".