21667101481 has 2 divisors, whose sum is σ = 21667101482. Its totient is φ = 21667101480.

The previous prime is 21667101439. The next prime is 21667101509. The reversal of 21667101481 is 18410176612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14959491481 + 6707610000 = 122309^2 + 81900^2 .

It is a cyclic number.

It is not a de Polignac number, because 21667101481 - 2⁹ = 21667100969 is a prime.

It is a super-2 number, since 2×21667101481² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21667101481.

It is not a weakly prime, because it can be changed into another prime (21667101431) 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, 10833550740 + 10833550741.

It is an arithmetic number, because the mean of its divisors is an integer number (10833550741).

Almost surely, 2^21667101481 is an apocalyptic number.

It is an amenable number.

21667101481 is a deficient number, since it is larger than the sum of its proper divisors (1).

21667101481 is an equidigital number, since it uses as much as digits as its factorization.

21667101481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 37.

The spelling of 21667101481 in words is "twenty-one billion, six hundred sixty-seven million, one hundred one thousand, four hundred eighty-one".