21225053315509 has 2 divisors, whose sum is σ = 21225053315510. Its totient is φ = 21225053315508.

The previous prime is 21225053315429. The next prime is 21225053315549. The reversal of 21225053315509 is 90551335052212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18203209976484 + 3021843339025 = 4266522^2 + 1738345^2 .

It is a cyclic number.

It is not a de Polignac number, because 21225053315509 - 2²³ = 21225044926901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21225053315549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612526657754 + 10612526657755.

It is an arithmetic number, because the mean of its divisors is an integer number (10612526657755).

Almost surely, 2^{21225053315509} is an apocalyptic number.

It is an amenable number.

21225053315509 is a deficient number, since it is larger than the sum of its proper divisors (1).

21225053315509 is an equidigital number, since it uses as much as digits as its factorization.

21225053315509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 405000, while the sum is 43.

The spelling of 21225053315509 in words is "twenty-one trillion, two hundred twenty-five billion, fifty-three million, three hundred fifteen thousand, five hundred nine".