21000012100247 has 2 divisors, whose sum is σ = 21000012100248. Its totient is φ = 21000012100246.

The previous prime is 21000012100219. The next prime is 21000012100279. The reversal of 21000012100247 is 74200121000012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21000012100247 - 2¹⁶ = 21000012034711 is a prime.

It is a super-2 number, since 2×21000012100247² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000012100297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500006050123 + 10500006050124.

It is an arithmetic number, because the mean of its divisors is an integer number (10500006050124).

Almost surely, 2^{21000012100247} is an apocalyptic number.

21000012100247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000012100247 is an equidigital number, since it uses as much as digits as its factorization.

21000012100247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 224, while the sum is 20.

Adding to 21000012100247 its reverse (74200121000012), we get a palindrome (95200133100259).

The spelling of 21000012100247 in words is "twenty-one trillion, twelve million, one hundred thousand, two hundred forty-seven".