20151211 has 4 divisors (see below), whose sum is σ = 20161152. Its totient is φ = 20141272.

The previous prime is 20151181. The next prime is 20151221. The reversal of 20151211 is 11215102.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 11215102 = 2 ⋅5607551.

It is a cyclic number.

It is not a de Polignac number, because 20151211 - 2⁵ = 20151179 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20151191 and 20151200.

It is not an unprimeable number, because it can be changed into a prime (20151221) 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, 715 + ... + 6388.

It is an arithmetic number, because the mean of its divisors is an integer number (5040288).

Almost surely, 2^20151211 is an apocalyptic number.

20151211 is a deficient number, since it is larger than the sum of its proper divisors (9941).

20151211 is an equidigital number, since it uses as much as digits as its factorization.

20151211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9940.

The product of its (nonzero) digits is 20, while the sum is 13.

The square root of 20151211 is about 4489.0100244932. The cubic root of 20151211 is about 272.1241278537.

Adding to 20151211 its reverse (11215102), we get a palindrome (31366313).

The spelling of 20151211 in words is "twenty million, one hundred fifty-one thousand, two hundred eleven".