21661044464099 has 2 divisors, whose sum is σ = 21661044464100. Its totient is φ = 21661044464098.

The previous prime is 21661044464063. The next prime is 21661044464153. The reversal of 21661044464099 is 99046444016612.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21661044464099 is a prime.

It is not a weakly prime, because it can be changed into another prime (21661044964099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10830522232049 + 10830522232050.

It is an arithmetic number, because the mean of its divisors is an integer number (10830522232050).

Almost surely, 2^{21661044464099} is an apocalyptic number.

21661044464099 is a deficient number, since it is larger than the sum of its proper divisors (1).

21661044464099 is an equidigital number, since it uses as much as digits as its factorization.

21661044464099 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8957952, while the sum is 56.

The spelling of 21661044464099 in words is "twenty-one trillion, six hundred sixty-one billion, forty-four million, four hundred sixty-four thousand, ninety-nine".