21533215439 has 2 divisors, whose sum is σ = 21533215440. Its totient is φ = 21533215438.

The previous prime is 21533215433. The next prime is 21533215481. The reversal of 21533215439 is 93451233512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21533215439 - 2⁸ = 21533215183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21533215433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10766607719 + 10766607720.

It is an arithmetic number, because the mean of its divisors is an integer number (10766607720).

Almost surely, 2^21533215439 is an apocalyptic number.

21533215439 is a deficient number, since it is larger than the sum of its proper divisors (1).

21533215439 is an equidigital number, since it uses as much as digits as its factorization.

21533215439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 97200, while the sum is 38.

The spelling of 21533215439 in words is "twenty-one billion, five hundred thirty-three million, two hundred fifteen thousand, four hundred thirty-nine".