21213320077 has 2 divisors, whose sum is σ = 21213320078. Its totient is φ = 21213320076.

The previous prime is 21213320021. The next prime is 21213320083. The reversal of 21213320077 is 77002331212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11925950436 + 9287369641 = 109206^2 + 96371^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213320077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213320017) 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, 10606660038 + 10606660039.

It is an arithmetic number, because the mean of its divisors is an integer number (10606660039).

Almost surely, 2^21213320077 is an apocalyptic number.

It is an amenable number.

21213320077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213320077 is an equidigital number, since it uses as much as digits as its factorization.

21213320077 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3528, while the sum is 28.

Adding to 21213320077 its reverse (77002331212), we get a palindrome (98215651289).

The spelling of 21213320077 in words is "twenty-one billion, two hundred thirteen million, three hundred twenty thousand, seventy-seven".