21241199781943 has 2 divisors, whose sum is σ = 21241199781944. Its totient is φ = 21241199781942.

The previous prime is 21241199781889. The next prime is 21241199781961. The reversal of 21241199781943 is 34918799114212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21241199781943 - 2¹⁷ = 21241199650871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21241193781943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620599890971 + 10620599890972.

It is an arithmetic number, because the mean of its divisors is an integer number (10620599890972).

Almost surely, 2^{21241199781943} is an apocalyptic number.

21241199781943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21241199781943 is an equidigital number, since it uses as much as digits as its factorization.

21241199781943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7838208, while the sum is 61.

The spelling of 21241199781943 in words is "twenty-one trillion, two hundred forty-one billion, one hundred ninety-nine million, seven hundred eighty-one thousand, nine hundred forty-three".