2100021201857 has 2 divisors, whose sum is σ = 2100021201858. Its totient is φ = 2100021201856.

The previous prime is 2100021201739. The next prime is 2100021201893. The reversal of 2100021201857 is 7581021200012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1487873006656 + 612148195201 = 1219784^2 + 782399^2 .

It is a cyclic number.

It is not a de Polignac number, because 2100021201857 - 2¹² = 2100021197761 is a prime.

It is not a weakly prime, because it can be changed into another prime (2100021201457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050010600928 + 1050010600929.

It is an arithmetic number, because the mean of its divisors is an integer number (1050010600929).

Almost surely, 2^{2100021201857} is an apocalyptic number.

It is an amenable number.

2100021201857 is a deficient number, since it is larger than the sum of its proper divisors (1).

2100021201857 is an equidigital number, since it uses as much as digits as its factorization.

2100021201857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2240, while the sum is 29.

Adding to 2100021201857 its reverse (7581021200012), we get a palindrome (9681042401869).

The spelling of 2100021201857 in words is "two trillion, one hundred billion, twenty-one million, two hundred one thousand, eight hundred fifty-seven".