21425321647 has 2 divisors, whose sum is σ = 21425321648. Its totient is φ = 21425321646.

The previous prime is 21425321591. The next prime is 21425321653. The reversal of 21425321647 is 74612352412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21425321647 - 2¹¹ = 21425319599 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21425321447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10712660823 + 10712660824.

It is an arithmetic number, because the mean of its divisors is an integer number (10712660824).

Almost surely, 2^21425321647 is an apocalyptic number.

21425321647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21425321647 is an equidigital number, since it uses as much as digits as its factorization.

21425321647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 37.

The spelling of 21425321647 in words is "twenty-one billion, four hundred twenty-five million, three hundred twenty-one thousand, six hundred forty-seven".