21766548697 has 2 divisors, whose sum is σ = 21766548698. Its totient is φ = 21766548696.

The previous prime is 21766548667. The next prime is 21766548703. The reversal of 21766548697 is 79684566712.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14612941456 + 7153607241 = 120884^2 + 84579^2 .

It is a cyclic number.

It is not a de Polignac number, because 21766548697 - 2⁷ = 21766548569 is a prime.

It is not a weakly prime, because it can be changed into another prime (21766548667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10883274348 + 10883274349.

It is an arithmetic number, because the mean of its divisors is an integer number (10883274349).

Almost surely, 2^21766548697 is an apocalyptic number.

It is an amenable number.

21766548697 is a deficient number, since it is larger than the sum of its proper divisors (1).

21766548697 is an equidigital number, since it uses as much as digits as its factorization.

21766548697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30481920, while the sum is 61.

The spelling of 21766548697 in words is "twenty-one billion, seven hundred sixty-six million, five hundred forty-eight thousand, six hundred ninety-seven".