21203202123 has 12 divisors (see below), whose sum is σ = 30652535160. Its totient is φ = 14123612256.

The previous prime is 21203202067. The next prime is 21203202131. The reversal of 21203202123 is 32120230212.

It is not a de Polignac number, because 21203202123 - 2¹⁷ = 21203071051 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21203202096 and 21203202105.

It is not an unprimeable number, because it can be changed into a prime (21203202523) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 976653 + ... + 998126.

It is an arithmetic number, because the mean of its divisors is an integer number (2554377930).

Almost surely, 2^21203202123 is an apocalyptic number.

21203202123 is a deficient number, since it is larger than the sum of its proper divisors (9449333037).

21203202123 is a wasteful number, since it uses less digits than its factorization.

21203202123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1975978 (or 1975975 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

Adding to 21203202123 its reverse (32120230212), we get a palindrome (53323432335).

The spelling of 21203202123 in words is "twenty-one billion, two hundred three million, two hundred two thousand, one hundred twenty-three".