20855587 has 4 divisors (see below), whose sum is σ = 20871000. Its totient is φ = 20840176.

The previous prime is 20855581. The next prime is 20855603. The reversal of 20855587 is 78555802.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20855587 is a prime.

It is a super-2 number, since 2×20855587² = 869911018229138, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20855581) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5458 + ... + 8455.

It is an arithmetic number, because the mean of its divisors is an integer number (5217750).

Almost surely, 2^20855587 is an apocalyptic number.

20855587 is a deficient number, since it is larger than the sum of its proper divisors (15413).

20855587 is a wasteful number, since it uses less digits than its factorization.

20855587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15412.

The product of its (nonzero) digits is 112000, while the sum is 40.

The square root of 20855587 is about 4566.7917622769. The cubic root of 20855587 is about 275.2585425288.

It can be divided in two parts, 2085558 and 7, that multiplied together give a triangular number (14598906 = T₅₄₀₃).

The spelling of 20855587 in words is "twenty million, eight hundred fifty-five thousand, five hundred eighty-seven".