21203031673 has 2 divisors, whose sum is σ = 21203031674. Its totient is φ = 21203031672.

The previous prime is 21203031659. The next prime is 21203031701. The reversal of 21203031673 is 37613030212.

It is an a-pointer prime, because the next prime (21203031701) can be obtained adding 21203031673 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19320166009 + 1882865664 = 138997^2 + 43392^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203031673 - 2¹³ = 21203023481 is a prime.

It is not a weakly prime, because it can be changed into another prime (21203031613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601515836 + 10601515837.

It is an arithmetic number, because the mean of its divisors is an integer number (10601515837).

Almost surely, 2^21203031673 is an apocalyptic number.

It is an amenable number.

21203031673 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203031673 is an equidigital number, since it uses as much as digits as its factorization.

21203031673 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 28.

Adding to 21203031673 its reverse (37613030212), we get a palindrome (58816061885).

The spelling of 21203031673 in words is "twenty-one billion, two hundred three million, thirty-one thousand, six hundred seventy-three".