20439913 has 8 divisors (see below), whose sum is σ = 22062600. Its totient is φ = 18824448.

The previous prime is 20439911. The next prime is 20439917. The reversal of 20439913 is 31993402.

It can be written as a sum of positive squares in 4 ways, for example, as 6801664 + 13638249 = 2608^2 + 3693^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20439913 - 2¹ = 20439911 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20439911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5073 + ... + 8161.

It is an arithmetic number, because the mean of its divisors is an integer number (2757825).

Almost surely, 2^20439913 is an apocalyptic number.

It is an amenable number.

20439913 is a deficient number, since it is larger than the sum of its proper divisors (1622687).

20439913 is a wasteful number, since it uses less digits than its factorization.

20439913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3611.

The product of its (nonzero) digits is 5832, while the sum is 31.

The square root of 20439913 is about 4521.0522005392. The cubic root of 20439913 is about 273.4175249604.

The spelling of 20439913 in words is "twenty million, four hundred thirty-nine thousand, nine hundred thirteen".