20872405 has 8 divisors (see below), whose sum is σ = 25128792. Its totient is φ = 16643328.

The previous prime is 20872387. The next prime is 20872409. The reversal of 20872405 is 50427802.

It can be written as a sum of positive squares in 4 ways, for example, as 432964 + 20439441 = 658^2 + 4521^2 .

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 20872405 - 2¹³ = 20864213 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 (20872409) 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, 5104 + ... + 8233.

It is an arithmetic number, because the mean of its divisors is an integer number (3141099).

Almost surely, 2^20872405 is an apocalyptic number.

It is an amenable number.

20872405 is a deficient number, since it is larger than the sum of its proper divisors (4256387).

20872405 is a wasteful number, since it uses less digits than its factorization.

20872405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13655.

The product of its (nonzero) digits is 4480, while the sum is 28.

The square root of 20872405 is about 4568.6327276331. The cubic root of 20872405 is about 275.3325123858.

The spelling of 20872405 in words is "twenty million, eight hundred seventy-two thousand, four hundred five".