21300442109 has 2 divisors, whose sum is σ = 21300442110. Its totient is φ = 21300442108.

The previous prime is 21300442091. The next prime is 21300442123. The reversal of 21300442109 is 90124400312.

Together with previous prime (21300442091) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18077609209 + 3222832900 = 134453^2 + 56770^2 .

It is a cyclic number.

It is not a de Polignac number, because 21300442109 - 2¹² = 21300438013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21300442129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650221054 + 10650221055.

It is an arithmetic number, because the mean of its divisors is an integer number (10650221055).

Almost surely, 2^21300442109 is an apocalyptic number.

It is an amenable number.

21300442109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21300442109 is an equidigital number, since it uses as much as digits as its factorization.

21300442109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 26.

The spelling of 21300442109 in words is "twenty-one billion, three hundred million, four hundred forty-two thousand, one hundred nine".