21001012111943 has 2 divisors, whose sum is σ = 21001012111944. Its totient is φ = 21001012111942.

The previous prime is 21001012111927. The next prime is 21001012112023. The reversal of 21001012111943 is 34911121010012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21001012111943 - 2⁴ = 21001012111927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001012111903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500506055971 + 10500506055972.

It is an arithmetic number, because the mean of its divisors is an integer number (10500506055972).

Almost surely, 2^{21001012111943} is an apocalyptic number.

21001012111943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001012111943 is an equidigital number, since it uses as much as digits as its factorization.

21001012111943 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 26.

Adding to 21001012111943 its reverse (34911121010012), we get a palindrome (55912133121955).

The spelling of 21001012111943 in words is "twenty-one trillion, one billion, twelve million, one hundred eleven thousand, nine hundred forty-three".