20406013 has 4 divisors (see below), whose sum is σ = 20555100. Its totient is φ = 20256928.

The previous prime is 20406011. The next prime is 20406017. The reversal of 20406013 is 31060402.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15856324 + 4549689 = 3982^2 + 2133^2 .

It is a cyclic number.

It is not a de Polignac number, because 20406013 - 2¹ = 20406011 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 (20406011) 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, 74338 + ... + 74611.

It is an arithmetic number, because the mean of its divisors is an integer number (5138775).

Almost surely, 2^20406013 is an apocalyptic number.

It is an amenable number.

20406013 is a deficient number, since it is larger than the sum of its proper divisors (149087).

20406013 is a wasteful number, since it uses less digits than its factorization.

20406013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149086.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 20406013 is about 4517.3015174991. The cubic root of 20406013 is about 273.2662851938.

Adding to 20406013 its reverse (31060402), we get a palindrome (51466415).

The spelling of 20406013 in words is "twenty million, four hundred six thousand, thirteen".