21207534401 has 2 divisors, whose sum is σ = 21207534402. Its totient is φ = 21207534400.

The previous prime is 21207534389. The next prime is 21207534407. The reversal of 21207534401 is 10443570212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13047122176 + 8160412225 = 114224^2 + 90335^2 .

It is a cyclic number.

It is not a de Polignac number, because 21207534401 - 2¹⁰ = 21207533377 is a prime.

It is not a weakly prime, because it can be changed into another prime (21207534407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10603767200 + 10603767201.

It is an arithmetic number, because the mean of its divisors is an integer number (10603767201).

Almost surely, 2^21207534401 is an apocalyptic number.

It is an amenable number.

21207534401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21207534401 is an equidigital number, since it uses as much as digits as its factorization.

21207534401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6720, while the sum is 29.

The spelling of 21207534401 in words is "twenty-one billion, two hundred seven million, five hundred thirty-four thousand, four hundred one".