21203030123 has 4 divisors (see below), whose sum is σ = 23130578328. Its totient is φ = 19275481920.

The previous prime is 21203030099. The next prime is 21203030129. The reversal of 21203030123 is 32103030212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21203030123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21203030129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 963774086 + ... + 963774107.

It is an arithmetic number, because the mean of its divisors is an integer number (5782644582).

Almost surely, 2^21203030123 is an apocalyptic number.

21203030123 is a deficient number, since it is larger than the sum of its proper divisors (1927548205).

21203030123 is a wasteful number, since it uses less digits than its factorization.

21203030123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1927548204.

The product of its (nonzero) digits is 216, while the sum is 17.

Adding to 21203030123 its reverse (32103030212), we get a palindrome (53306060335).

The spelling of 21203030123 in words is "twenty-one billion, two hundred three million, thirty thousand, one hundred twenty-three".