21023442191 has 2 divisors, whose sum is σ = 21023442192. Its totient is φ = 21023442190.

The previous prime is 21023442179. The next prime is 21023442227. The reversal of 21023442191 is 19124432012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21023442191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21023447191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511721095 + 10511721096.

It is an arithmetic number, because the mean of its divisors is an integer number (10511721096).

Almost surely, 2^21023442191 is an apocalyptic number.

21023442191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023442191 is an equidigital number, since it uses as much as digits as its factorization.

21023442191 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 21023442191 in words is "twenty-one billion, twenty-three million, four hundred forty-two thousand, one hundred ninety-one".