20587251 has 4 divisors (see below), whose sum is σ = 27449672. Its totient is φ = 13724832.

The previous prime is 20587249. The next prime is 20587297. The reversal of 20587251 is 15278502.

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

It is not a de Polignac number, because 20587251 - 2¹ = 20587249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20587201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3431206 + ... + 3431211.

It is an arithmetic number, because the mean of its divisors is an integer number (6862418).

Almost surely, 2^20587251 is an apocalyptic number.

20587251 is a deficient number, since it is larger than the sum of its proper divisors (6862421).

20587251 is an equidigital number, since it uses as much as digits as its factorization.

20587251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6862420.

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 20587251 is about 4537.3175996397. The cubic root of 20587251 is about 274.0729155758.

The spelling of 20587251 in words is "twenty million, five hundred eighty-seven thousand, two hundred fifty-one".