21169038661 has 2 divisors, whose sum is σ = 21169038662. Its totient is φ = 21169038660.

The previous prime is 21169038629. The next prime is 21169038739. The reversal of 21169038661 is 16683096112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20572164900 + 596873761 = 143430^2 + 24431^2 .

It is a cyclic number.

It is not a de Polignac number, because 21169038661 - 2⁵ = 21169038629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21169035661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10584519330 + 10584519331.

It is an arithmetic number, because the mean of its divisors is an integer number (10584519331).

Almost surely, 2^21169038661 is an apocalyptic number.

It is an amenable number.

21169038661 is a deficient number, since it is larger than the sum of its proper divisors (1).

21169038661 is an equidigital number, since it uses as much as digits as its factorization.

21169038661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 93312, while the sum is 43.

The spelling of 21169038661 in words is "twenty-one billion, one hundred sixty-nine million, thirty-eight thousand, six hundred sixty-one".