21000011100997 has 2 divisors, whose sum is σ = 21000011100998. Its totient is φ = 21000011100996.

The previous prime is 21000011100947. The next prime is 21000011101051. The reversal of 21000011100997 is 79900111000012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15591963179556 + 5408047921441 = 3948666^2 + 2325521^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000011100997 - 2¹⁵ = 21000011068229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000011100947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500005550498 + 10500005550499.

It is an arithmetic number, because the mean of its divisors is an integer number (10500005550499).

Almost surely, 2^{21000011100997} is an apocalyptic number.

It is an amenable number.

21000011100997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000011100997 is an equidigital number, since it uses as much as digits as its factorization.

21000011100997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1134, while the sum is 31.

The spelling of 21000011100997 in words is "twenty-one trillion, eleven million, one hundred thousand, nine hundred ninety-seven".