21123302191 has 2 divisors, whose sum is σ = 21123302192. Its totient is φ = 21123302190.

The previous prime is 21123302107. The next prime is 21123302197. The reversal of 21123302191 is 19120332112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21123302191 - 2¹³ = 21123293999 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21123302197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561651095 + 10561651096.

It is an arithmetic number, because the mean of its divisors is an integer number (10561651096).

Almost surely, 2^21123302191 is an apocalyptic number.

21123302191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123302191 is an equidigital number, since it uses as much as digits as its factorization.

21123302191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 25.

The spelling of 21123302191 in words is "twenty-one billion, one hundred twenty-three million, three hundred two thousand, one hundred ninety-one".