21019018843 has 2 divisors, whose sum is σ = 21019018844. Its totient is φ = 21019018842.

The previous prime is 21019018723. The next prime is 21019018859. The reversal of 21019018843 is 34881091012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21019018843 is a prime.

It is not a weakly prime, because it can be changed into another prime (21019018873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10509509421 + 10509509422.

It is an arithmetic number, because the mean of its divisors is an integer number (10509509422).

Almost surely, 2^21019018843 is an apocalyptic number.

21019018843 is a deficient number, since it is larger than the sum of its proper divisors (1).

21019018843 is an equidigital number, since it uses as much as digits as its factorization.

21019018843 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 37.

The spelling of 21019018843 in words is "twenty-one billion, nineteen million, eighteen thousand, eight hundred forty-three".