21000421003 has 2 divisors, whose sum is σ = 21000421004. Its totient is φ = 21000421002.

The previous prime is 21000420983. The next prime is 21000421033. The reversal of 21000421003 is 30012400012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21000421003 - 2¹⁷ = 21000289931 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000421033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500210501 + 10500210502.

It is an arithmetic number, because the mean of its divisors is an integer number (10500210502).

Almost surely, 2^21000421003 is an apocalyptic number.

21000421003 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000421003 is an equidigital number, since it uses as much as digits as its factorization.

21000421003 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 13.

Adding to 21000421003 its reverse (30012400012), we get a palindrome (51012821015).

The spelling of 21000421003 in words is "twenty-one billion, four hundred twenty-one thousand, three".