21298047857 has 2 divisors, whose sum is σ = 21298047858. Its totient is φ = 21298047856.

The previous prime is 21298047851. The next prime is 21298047871. The reversal of 21298047857 is 75874089212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12738282496 + 8559765361 = 112864^2 + 92519^2 .

It is a cyclic number.

It is not a de Polignac number, because 21298047857 - 2¹² = 21298043761 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21298047799 and 21298047808.

It is not a weakly prime, because it can be changed into another prime (21298047851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10649023928 + 10649023929.

It is an arithmetic number, because the mean of its divisors is an integer number (10649023929).

Almost surely, 2^21298047857 is an apocalyptic number.

It is an amenable number.

21298047857 is a deficient number, since it is larger than the sum of its proper divisors (1).

21298047857 is an equidigital number, since it uses as much as digits as its factorization.

21298047857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2257920, while the sum is 53.

The spelling of 21298047857 in words is "twenty-one billion, two hundred ninety-eight million, forty-seven thousand, eight hundred fifty-seven".