21264561211 has 2 divisors, whose sum is σ = 21264561212. Its totient is φ = 21264561210.

The previous prime is 21264561209. The next prime is 21264561343. The reversal of 21264561211 is 11216546212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21264561211 - 2¹ = 21264561209 is a prime.

Together with 21264561209, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21264561511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10632280605 + 10632280606.

It is an arithmetic number, because the mean of its divisors is an integer number (10632280606).

Almost surely, 2^21264561211 is an apocalyptic number.

21264561211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21264561211 is an equidigital number, since it uses as much as digits as its factorization.

21264561211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 31.

The spelling of 21264561211 in words is "twenty-one billion, two hundred sixty-four million, five hundred sixty-one thousand, two hundred eleven".