21444778601 has 2 divisors, whose sum is σ = 21444778602. Its totient is φ = 21444778600.

The previous prime is 21444778591. The next prime is 21444778609. The reversal of 21444778601 is 10687744412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11556465001 + 9888313600 = 107501^2 + 99440^2 .

It is a cyclic number.

It is not a de Polignac number, because 21444778601 - 2¹⁰ = 21444777577 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21444778609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10722389300 + 10722389301.

It is an arithmetic number, because the mean of its divisors is an integer number (10722389301).

Almost surely, 2^21444778601 is an apocalyptic number.

It is an amenable number.

21444778601 is a deficient number, since it is larger than the sum of its proper divisors (1).

21444778601 is an equidigital number, since it uses as much as digits as its factorization.

21444778601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 301056, while the sum is 44.

The spelling of 21444778601 in words is "twenty-one billion, four hundred forty-four million, seven hundred seventy-eight thousand, six hundred one".