21466011661 has 2 divisors, whose sum is σ = 21466011662. Its totient is φ = 21466011660.

The previous prime is 21466011643. The next prime is 21466011689. The reversal of 21466011661 is 16611066412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13687830025 + 7778181636 = 116995^2 + 88194^2 .

It is a cyclic number.

It is not a de Polignac number, because 21466011661 - 2¹⁷ = 21465880589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21466011761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10733005830 + 10733005831.

It is an arithmetic number, because the mean of its divisors is an integer number (10733005831).

Almost surely, 2^21466011661 is an apocalyptic number.

It is an amenable number.

21466011661 is a deficient number, since it is larger than the sum of its proper divisors (1).

21466011661 is an equidigital number, since it uses as much as digits as its factorization.

21466011661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 34.

The spelling of 21466011661 in words is "twenty-one billion, four hundred sixty-six million, eleven thousand, six hundred sixty-one".