21210023203 has 4 divisors (see below), whose sum is σ = 21246782920. Its totient is φ = 21173263488.

The previous prime is 21210023143. The next prime is 21210023251. The reversal of 21210023203 is 30232001212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21210023203 - 2¹³ = 21210015011 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210026203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18378993 + ... + 18380146.

It is an arithmetic number, because the mean of its divisors is an integer number (5311695730).

Almost surely, 2^21210023203 is an apocalyptic number.

21210023203 is a deficient number, since it is larger than the sum of its proper divisors (36759717).

21210023203 is an equidigital number, since it uses as much as digits as its factorization.

21210023203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36759716.

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21210023203 its reverse (30232001212), we get a palindrome (51442024415).

The spelling of 21210023203 in words is "twenty-one billion, two hundred ten million, twenty-three thousand, two hundred three".