20855315647 has 2 divisors, whose sum is σ = 20855315648. Its totient is φ = 20855315646.

The previous prime is 20855315603. The next prime is 20855315669. The reversal of 20855315647 is 74651355802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20855315647 - 2¹⁵ = 20855282879 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20855315597 and 20855315606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20855115647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10427657823 + 10427657824.

It is an arithmetic number, because the mean of its divisors is an integer number (10427657824).

Almost surely, 2^20855315647 is an apocalyptic number.

20855315647 is a deficient number, since it is larger than the sum of its proper divisors (1).

20855315647 is an equidigital number, since it uses as much as digits as its factorization.

20855315647 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008000, while the sum is 46.

The spelling of 20855315647 in words is "twenty billion, eight hundred fifty-five million, three hundred fifteen thousand, six hundred forty-seven".