20840413 has 4 divisors (see below), whose sum is σ = 22735008. Its totient is φ = 18945820.

The previous prime is 20840399. The next prime is 20840429. The reversal of 20840413 is 31404802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20840413 - 2⁵ = 20840381 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 (20840513) 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, 947281 + ... + 947302.

It is an arithmetic number, because the mean of its divisors is an integer number (5683752).

Almost surely, 2^20840413 is an apocalyptic number.

It is an amenable number.

20840413 is a deficient number, since it is larger than the sum of its proper divisors (1894595).

20840413 is a wasteful number, since it uses less digits than its factorization.

20840413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1894594.

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 20840413 is about 4565.1301186275. The cubic root of 20840413 is about 275.1917692703.

The spelling of 20840413 in words is "twenty million, eight hundred forty thousand, four hundred thirteen".