21121210123 has 8 divisors (see below), whose sum is σ = 22751091216. Its totient is φ = 19492068000.

The previous prime is 21121210087. The next prime is 21121210151. The reversal of 21121210123 is 32101212112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21121210123 - 2³³ = 12531275531 is a prime.

It is a super-2 number, since 2×21121210123² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121210097 and 21121210106.

It is not an unprimeable number, because it can be changed into a prime (21121210153) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124648 + ... + 240373.

It is an arithmetic number, because the mean of its divisors is an integer number (2843886402).

Almost surely, 2^21121210123 is an apocalyptic number.

21121210123 is a deficient number, since it is larger than the sum of its proper divisors (1629881093).

21121210123 is a wasteful number, since it uses less digits than its factorization.

21121210123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369485.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21121210123 its reverse (32101212112), we get a palindrome (53222422235).

The spelling of 21121210123 in words is "twenty-one billion, one hundred twenty-one million, two hundred ten thousand, one hundred twenty-three".