21973944497 has 2 divisors, whose sum is σ = 21973944498. Its totient is φ = 21973944496.

The previous prime is 21973944457. The next prime is 21973944511. The reversal of 21973944497 is 79444937912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21512382241 + 461562256 = 146671^2 + 21484^2 .

It is a cyclic number.

It is not a de Polignac number, because 21973944497 - 2²⁰ = 21972895921 is a prime.

It is not a weakly prime, because it can be changed into another prime (21973944437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10986972248 + 10986972249.

It is an arithmetic number, because the mean of its divisors is an integer number (10986972249).

Almost surely, 2^21973944497 is an apocalyptic number.

It is an amenable number.

21973944497 is a deficient number, since it is larger than the sum of its proper divisors (1).

21973944497 is an equidigital number, since it uses as much as digits as its factorization.

21973944497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13716864, while the sum is 59.

The spelling of 21973944497 in words is "twenty-one billion, nine hundred seventy-three million, nine hundred forty-four thousand, four hundred ninety-seven".