21210123111 has 32 divisors (see below), whose sum is σ = 30775261440. Its totient is φ = 12949300224.

The previous prime is 21210123107. The next prime is 21210123113. The reversal of 21210123111 is 11132101212.

It is not a de Polignac number, because 21210123111 - 2² = 21210123107 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210123113) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 193141 + ... + 282353.

It is an arithmetic number, because the mean of its divisors is an integer number (961726920).

Almost surely, 2^21210123111 is an apocalyptic number.

21210123111 is a deficient number, since it is larger than the sum of its proper divisors (9565138329).

21210123111 is a wasteful number, since it uses less digits than its factorization.

21210123111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89375.

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 21210123111 its reverse (11132101212), we get a palindrome (32342224323).

The spelling of 21210123111 in words is "twenty-one billion, two hundred ten million, one hundred twenty-three thousand, one hundred eleven".