21211155157 has 2 divisors, whose sum is σ = 21211155158. Its totient is φ = 21211155156.

The previous prime is 21211155139. The next prime is 21211155181. The reversal of 21211155157 is 75155111212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20372994756 + 838160401 = 142734^2 + 28951^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211155157 - 2¹¹ = 21211153109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211155107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605577578 + 10605577579.

It is an arithmetic number, because the mean of its divisors is an integer number (10605577579).

Almost surely, 2^21211155157 is an apocalyptic number.

It is an amenable number.

21211155157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211155157 is an equidigital number, since it uses as much as digits as its factorization.

21211155157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3500, while the sum is 31.

Adding to 21211155157 its reverse (75155111212), we get a palindrome (96366266369).

The spelling of 21211155157 in words is "twenty-one billion, two hundred eleven million, one hundred fifty-five thousand, one hundred fifty-seven".