21725255647 has 2 divisors, whose sum is σ = 21725255648. Its totient is φ = 21725255646.

The previous prime is 21725255639. The next prime is 21725255677. The reversal of 21725255647 is 74655252712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21725255647 - 2³ = 21725255639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21725255597 and 21725255606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21725255677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10862627823 + 10862627824.

It is an arithmetic number, because the mean of its divisors is an integer number (10862627824).

Almost surely, 2^21725255647 is an apocalyptic number.

21725255647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21725255647 is an equidigital number, since it uses as much as digits as its factorization.

21725255647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1176000, while the sum is 46.

The spelling of 21725255647 in words is "twenty-one billion, seven hundred twenty-five million, two hundred fifty-five thousand, six hundred forty-seven".