21507122011 has 2 divisors, whose sum is σ = 21507122012. Its totient is φ = 21507122010.

The previous prime is 21507121949. The next prime is 21507122017. The reversal of 21507122011 is 11022170512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21507122011 - 2¹³ = 21507113819 is a prime.

It is not a weakly prime, because it can be changed into another prime (21507122017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10753561005 + 10753561006.

It is an arithmetic number, because the mean of its divisors is an integer number (10753561006).

Almost surely, 2^21507122011 is an apocalyptic number.

21507122011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21507122011 is an equidigital number, since it uses as much as digits as its factorization.

21507122011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 280, while the sum is 22.

Adding to 21507122011 its reverse (11022170512), we get a palindrome (32529292523).

The spelling of 21507122011 in words is "twenty-one billion, five hundred seven million, one hundred twenty-two thousand, eleven".