20155211 has 4 divisors (see below), whose sum is σ = 20535552. Its totient is φ = 19774872.

The previous prime is 20155169. The next prime is 20155249. The reversal of 20155211 is 11255102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11255102 = 2 ⋅5627551.

It is a cyclic number.

It is not a de Polignac number, because 20155211 - 2⁶ = 20155147 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 20155211.

It is not an unprimeable number, because it can be changed into a prime (20155271) 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, 190091 + ... + 190196.

It is an arithmetic number, because the mean of its divisors is an integer number (5133888).

Almost surely, 2^20155211 is an apocalyptic number.

20155211 is a deficient number, since it is larger than the sum of its proper divisors (380341).

20155211 is an equidigital number, since it uses as much as digits as its factorization.

20155211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380340.

The product of its (nonzero) digits is 100, while the sum is 17.

The square root of 20155211 is about 4489.4555349173. The cubic root of 20155211 is about 272.1421321397.

The spelling of 20155211 in words is "twenty million, one hundred fifty-five thousand, two hundred eleven".