21163522661 has 2 divisors, whose sum is σ = 21163522662. Its totient is φ = 21163522660.

The previous prime is 21163522651. The next prime is 21163522733. The reversal of 21163522661 is 16622536112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18504160900 + 2659361761 = 136030^2 + 51569^2 .

It is a cyclic number.

It is not a de Polignac number, because 21163522661 - 2¹⁴ = 21163506277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21163522651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10581761330 + 10581761331.

It is an arithmetic number, because the mean of its divisors is an integer number (10581761331).

Almost surely, 2^21163522661 is an apocalyptic number.

It is an amenable number.

21163522661 is a deficient number, since it is larger than the sum of its proper divisors (1).

21163522661 is an equidigital number, since it uses as much as digits as its factorization.

21163522661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25920, while the sum is 35.

The spelling of 21163522661 in words is "twenty-one billion, one hundred sixty-three million, five hundred twenty-two thousand, six hundred sixty-one".