21154312211 has 2 divisors, whose sum is σ = 21154312212. Its totient is φ = 21154312210.

The previous prime is 21154312181. The next prime is 21154312213. The reversal of 21154312211 is 11221345112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21154312211 - 2⁶ = 21154312147 is a prime.

Together with 21154312213, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21154312213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577156105 + 10577156106.

It is an arithmetic number, because the mean of its divisors is an integer number (10577156106).

Almost surely, 2^21154312211 is an apocalyptic number.

21154312211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21154312211 is an equidigital number, since it uses as much as digits as its factorization.

21154312211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480, while the sum is 23.

Adding to 21154312211 its reverse (11221345112), we get a palindrome (32375657323).

The spelling of 21154312211 in words is "twenty-one billion, one hundred fifty-four million, three hundred twelve thousand, two hundred eleven".