21120202123 has 4 divisors (see below), whose sum is σ = 21121500400. Its totient is φ = 21118903848.

The previous prime is 21120202097. The next prime is 21120202139. The reversal of 21120202123 is 32120202112.

It is a happy number.

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 21120202123 - 2⁵ = 21120202091 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21120202097 and 21120202106.

It is not an unprimeable number, because it can be changed into a prime (21120202163) 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, 624423 + ... + 657376.

It is an arithmetic number, because the mean of its divisors is an integer number (5280375100).

Almost surely, 2^21120202123 is an apocalyptic number.

21120202123 is a deficient number, since it is larger than the sum of its proper divisors (1298277).

21120202123 is a wasteful number, since it uses less digits than its factorization.

21120202123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1298276.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21120202123 its reverse (32120202112), we get a palindrome (53240404235).

The spelling of 21120202123 in words is "twenty-one billion, one hundred twenty million, two hundred two thousand, one hundred twenty-three".