21916980493 has 2 divisors, whose sum is σ = 21916980494. Its totient is φ = 21916980492.

The previous prime is 21916980467. The next prime is 21916980497. The reversal of 21916980493 is 39408961912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17547506089 + 4369474404 = 132467^2 + 66102^2 .

It is a cyclic number.

It is not a de Polignac number, because 21916980493 - 2¹⁷ = 21916849421 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21916980493.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21916980497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10958490246 + 10958490247.

It is an arithmetic number, because the mean of its divisors is an integer number (10958490247).

Almost surely, 2^21916980493 is an apocalyptic number.

It is an amenable number.

21916980493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21916980493 is an equidigital number, since it uses as much as digits as its factorization.

21916980493 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 839808, while the sum is 52.

The spelling of 21916980493 in words is "twenty-one billion, nine hundred sixteen million, nine hundred eighty thousand, four hundred ninety-three".