21020043240403 has 2 divisors, whose sum is σ = 21020043240404. Its totient is φ = 21020043240402.

The previous prime is 21020043240389. The next prime is 21020043240419. The reversal of 21020043240403 is 30404234002012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21020043240403 - 2²¹ = 21020041143251 is a prime.

It is not a weakly prime, because it can be changed into another prime (21020043240433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510021620201 + 10510021620202.

It is an arithmetic number, because the mean of its divisors is an integer number (10510021620202).

Almost surely, 2^{21020043240403} is an apocalyptic number.

21020043240403 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020043240403 is an equidigital number, since it uses as much as digits as its factorization.

21020043240403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 25.

Adding to 21020043240403 its reverse (30404234002012), we get a palindrome (51424277242415).

The spelling of 21020043240403 in words is "twenty-one trillion, twenty billion, forty-three million, two hundred forty thousand, four hundred three".