21404143391 has 2 divisors, whose sum is σ = 21404143392. Its totient is φ = 21404143390.

The previous prime is 21404143379. The next prime is 21404143433. The reversal of 21404143391 is 19334140412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21404143391 - 2¹⁰ = 21404142367 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21404143991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10702071695 + 10702071696.

It is an arithmetic number, because the mean of its divisors is an integer number (10702071696).

Almost surely, 2^21404143391 is an apocalyptic number.

21404143391 is a deficient number, since it is larger than the sum of its proper divisors (1).

21404143391 is an equidigital number, since it uses as much as digits as its factorization.

21404143391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 32.

The spelling of 21404143391 in words is "twenty-one billion, four hundred four million, one hundred forty-three thousand, three hundred ninety-one".