21151112011 has 4 divisors (see below), whose sum is σ = 21173590224. Its totient is φ = 21128633800.

The previous prime is 21151111987. The next prime is 21151112027. The reversal of 21151112011 is 11021115112.

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

It is a cyclic number.

It is not a de Polignac number, because 21151112011 - 2¹³ = 21151103819 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21151112711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11237695 + ... + 11239576.

It is an arithmetic number, because the mean of its divisors is an integer number (5293397556).

Almost surely, 2^21151112011 is an apocalyptic number.

21151112011 is a deficient number, since it is larger than the sum of its proper divisors (22478213).

21151112011 is an equidigital number, since it uses as much as digits as its factorization.

21151112011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22478212.

The product of its (nonzero) digits is 20, while the sum is 16.

Adding to 21151112011 its reverse (11021115112), we get a palindrome (32172227123).

The spelling of 21151112011 in words is "twenty-one billion, one hundred fifty-one million, one hundred twelve thousand, eleven".