21242433391 has 2 divisors, whose sum is σ = 21242433392. Its totient is φ = 21242433390.

The previous prime is 21242433379. The next prime is 21242433463. The reversal of 21242433391 is 19333424212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21242433391 - 2¹⁵ = 21242400623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21242433361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621216695 + 10621216696.

It is an arithmetic number, because the mean of its divisors is an integer number (10621216696).

Almost surely, 2^21242433391 is an apocalyptic number.

21242433391 is a deficient number, since it is larger than the sum of its proper divisors (1).

21242433391 is an equidigital number, since it uses as much as digits as its factorization.

21242433391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 34.

The spelling of 21242433391 in words is "twenty-one billion, two hundred forty-two million, four hundred thirty-three thousand, three hundred ninety-one".