21533540211211 has 4 divisors (see below), whose sum is σ = 24609760241392. Its totient is φ = 18457320181032.

The previous prime is 21533540211187. The next prime is 21533540211257. The reversal of 21533540211211 is 11211204533512.

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 21533540211211 - 2⁷ = 21533540211083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21533540211511) 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, 1538110015080 + ... + 1538110015093.

It is an arithmetic number, because the mean of its divisors is an integer number (6152440060348).

Almost surely, 2^{21533540211211} is an apocalyptic number.

21533540211211 is a deficient number, since it is larger than the sum of its proper divisors (3076220030181).

21533540211211 is an equidigital number, since it uses as much as digits as its factorization.

21533540211211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3076220030180.

The product of its (nonzero) digits is 7200, while the sum is 31.

Adding to 21533540211211 its reverse (11211204533512), we get a palindrome (32744744744723).

The spelling of 21533540211211 in words is "twenty-one trillion, five hundred thirty-three billion, five hundred forty million, two hundred eleven thousand, two hundred eleven".