20287405 has 8 divisors (see below), whose sum is σ = 24375672. Its totient is φ = 16209408.

The previous prime is 20287391. The next prime is 20287411. The reversal of 20287405 is 50478202.

It can be written as a sum of positive squares in 4 ways, for example, as 1225449 + 19061956 = 1107^2 + 4366^2 .

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 20287405 - 2⁵ = 20287373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2809 + ... + 6961.

It is an arithmetic number, because the mean of its divisors is an integer number (3046959).

Almost surely, 2^20287405 is an apocalyptic number.

It is an amenable number.

20287405 is a deficient number, since it is larger than the sum of its proper divisors (4088267).

20287405 is an equidigital number, since it uses as much as digits as its factorization.

20287405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5135.

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

The square root of 20287405 is about 4504.1541936306. The cubic root of 20287405 is about 272.7358113657.

The spelling of 20287405 in words is "twenty million, two hundred eighty-seven thousand, four hundred five".