21816767057 has 2 divisors, whose sum is σ = 21816767058. Its totient is φ = 21816767056.

The previous prime is 21816767023. The next prime is 21816767083. The reversal of 21816767057 is 75076761812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21103663441 + 713103616 = 145271^2 + 26704^2 .

It is a cyclic number.

It is not a de Polignac number, because 21816767057 - 2¹⁴ = 21816750673 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21816766996 and 21816767014.

It is not a weakly prime, because it can be changed into another prime (21816767087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10908383528 + 10908383529.

It is an arithmetic number, because the mean of its divisors is an integer number (10908383529).

Almost surely, 2^21816767057 is an apocalyptic number.

It is an amenable number.

21816767057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21816767057 is an equidigital number, since it uses as much as digits as its factorization.

21816767057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 987840, while the sum is 50.

The spelling of 21816767057 in words is "twenty-one billion, eight hundred sixteen million, seven hundred sixty-seven thousand, fifty-seven".