21201122077 has 2 divisors, whose sum is σ = 21201122078. Its totient is φ = 21201122076.

The previous prime is 21201122069. The next prime is 21201122113. The reversal of 21201122077 is 77022110212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20791909636 + 409212441 = 144194^2 + 20229^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201122077 - 2³ = 21201122069 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201122027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600561038 + 10600561039.

It is an arithmetic number, because the mean of its divisors is an integer number (10600561039).

Almost surely, 2^21201122077 is an apocalyptic number.

It is an amenable number.

21201122077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201122077 is an equidigital number, since it uses as much as digits as its factorization.

21201122077 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 784, while the sum is 25.

Adding to 21201122077 its reverse (77022110212), we get a palindrome (98223232289).

The spelling of 21201122077 in words is "twenty-one billion, two hundred one million, one hundred twenty-two thousand, seventy-seven".