21315113377 has 2 divisors, whose sum is σ = 21315113378. Its totient is φ = 21315113376.

The previous prime is 21315113329. The next prime is 21315113399. The reversal of 21315113377 is 77331151312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19098963601 + 2216149776 = 138199^2 + 47076^2 .

It is a cyclic number.

It is not a de Polignac number, because 21315113377 - 2⁷ = 21315113249 is a prime.

It is not a weakly prime, because it can be changed into another prime (21315113327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10657556688 + 10657556689.

It is an arithmetic number, because the mean of its divisors is an integer number (10657556689).

Almost surely, 2^21315113377 is an apocalyptic number.

It is an amenable number.

21315113377 is a deficient number, since it is larger than the sum of its proper divisors (1).

21315113377 is an equidigital number, since it uses as much as digits as its factorization.

21315113377 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13230, while the sum is 34.

Adding to 21315113377 its reverse (77331151312), we get a palindrome (98646264689).

The spelling of 21315113377 in words is "twenty-one billion, three hundred fifteen million, one hundred thirteen thousand, three hundred seventy-seven".