21202144391 has 2 divisors, whose sum is σ = 21202144392. Its totient is φ = 21202144390.

The previous prime is 21202144333. The next prime is 21202144417. The reversal of 21202144391 is 19344120212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21202144391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21202144331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601072195 + 10601072196.

It is an arithmetic number, because the mean of its divisors is an integer number (10601072196).

Almost surely, 2^21202144391 is an apocalyptic number.

21202144391 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202144391 is an equidigital number, since it uses as much as digits as its factorization.

21202144391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 29.

The spelling of 21202144391 in words is "twenty-one billion, two hundred two million, one hundred forty-four thousand, three hundred ninety-one".