21013310977 has 2 divisors, whose sum is σ = 21013310978. Its totient is φ = 21013310976.

The previous prime is 21013310959. The next prime is 21013311001. The reversal of 21013310977 is 77901331012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20929698241 + 83612736 = 144671^2 + 9144^2 .

It is a cyclic number.

It is not a de Polignac number, because 21013310977 - 2²³ = 21004922369 is a prime.

It is a super-2 number, since 2×21013310977² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21013310947) 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, 10506655488 + 10506655489.

It is an arithmetic number, because the mean of its divisors is an integer number (10506655489).

Almost surely, 2^21013310977 is an apocalyptic number.

It is an amenable number.

21013310977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21013310977 is an equidigital number, since it uses as much as digits as its factorization.

21013310977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7938, while the sum is 34.

Adding to 21013310977 its reverse (77901331012), we get a palindrome (98914641989).

The spelling of 21013310977 in words is "twenty-one billion, thirteen million, three hundred ten thousand, nine hundred seventy-seven".