21213366011491 has 2 divisors, whose sum is σ = 21213366011492. Its totient is φ = 21213366011490.

The previous prime is 21213366011479. The next prime is 21213366011549. The reversal of 21213366011491 is 19411066331212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21213366011491 - 2⁹ = 21213366010979 is a prime.

It is not a weakly prime, because it can be changed into another prime (21213366011401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606683005745 + 10606683005746.

It is an arithmetic number, because the mean of its divisors is an integer number (10606683005746).

Almost surely, 2^{21213366011491} is an apocalyptic number.

21213366011491 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213366011491 is an equidigital number, since it uses as much as digits as its factorization.

21213366011491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 40.

The spelling of 21213366011491 in words is "twenty-one trillion, two hundred thirteen billion, three hundred sixty-six million, eleven thousand, four hundred ninety-one".