21126003391 has 2 divisors, whose sum is σ = 21126003392. Its totient is φ = 21126003390.

The previous prime is 21126003373. The next prime is 21126003421. The reversal of 21126003391 is 19330062112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21126003391 - 2⁵ = 21126003359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21126003191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10563001695 + 10563001696.

It is an arithmetic number, because the mean of its divisors is an integer number (10563001696).

Almost surely, 2^21126003391 is an apocalyptic number.

21126003391 is a deficient number, since it is larger than the sum of its proper divisors (1).

21126003391 is an equidigital number, since it uses as much as digits as its factorization.

21126003391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 28.

The spelling of 21126003391 in words is "twenty-one billion, one hundred twenty-six million, three thousand, three hundred ninety-one".