20487265 has 4 divisors (see below), whose sum is σ = 24584724. Its totient is φ = 16389808.

The previous prime is 20487251. The next prime is 20487289. The reversal of 20487265 is 56278402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56278402 = 2 ⋅28139201.

It can be written as a sum of positive squares in 2 ways, for example, as 2712609 + 17774656 = 1647^2 + 4216^2 .

It is a cyclic number.

It is not a de Polignac number, because 20487265 - 2¹¹ = 20485217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20487265.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2048722 + ... + 2048731.

It is an arithmetic number, because the mean of its divisors is an integer number (6146181).

Almost surely, 2^20487265 is an apocalyptic number.

It is an amenable number.

20487265 is a deficient number, since it is larger than the sum of its proper divisors (4097459).

20487265 is an equidigital number, since it uses as much as digits as its factorization.

20487265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4097458.

The product of its (nonzero) digits is 26880, while the sum is 34.

The square root of 20487265 is about 4526.2860051040. The cubic root of 20487265 is about 273.6284991417.

The spelling of 20487265 in words is "twenty million, four hundred eighty-seven thousand, two hundred sixty-five".