21203276729 has 2 divisors, whose sum is σ = 21203276730. Its totient is φ = 21203276728.

The previous prime is 21203276723. The next prime is 21203276749. The reversal of 21203276729 is 92767230212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11466126400 + 9737150329 = 107080^2 + 98677^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203276729 - 2⁸ = 21203276473 is a prime.

It is not a weakly prime, because it can be changed into another prime (21203276723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601638364 + 10601638365.

It is an arithmetic number, because the mean of its divisors is an integer number (10601638365).

Almost surely, 2^21203276729 is an apocalyptic number.

It is an amenable number.

21203276729 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203276729 is an equidigital number, since it uses as much as digits as its factorization.

21203276729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 127008, while the sum is 41.

The spelling of 21203276729 in words is "twenty-one billion, two hundred three million, two hundred seventy-six thousand, seven hundred twenty-nine".