21446989481 has 2 divisors, whose sum is σ = 21446989482. Its totient is φ = 21446989480.

The previous prime is 21446989463. The next prime is 21446989511. The reversal of 21446989481 is 18498964412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12399936025 + 9047053456 = 111355^2 + 95116^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21446989481 is a prime.

It is a super-2 number, since 2×21446989481² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21446989181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10723494740 + 10723494741.

It is an arithmetic number, because the mean of its divisors is an integer number (10723494741).

Almost surely, 2^21446989481 is an apocalyptic number.

It is an amenable number.

21446989481 is a deficient number, since it is larger than the sum of its proper divisors (1).

21446989481 is an equidigital number, since it uses as much as digits as its factorization.

21446989481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3981312, while the sum is 56.

The spelling of 21446989481 in words is "twenty-one billion, four hundred forty-six million, nine hundred eighty-nine thousand, four hundred eighty-one".