21211012123 has 8 divisors (see below), whose sum is σ = 24245185280. Its totient is φ = 18177846120.

The previous prime is 21211012117. The next prime is 21211012187. The reversal of 21211012123 is 32121011212.

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

It is a de Polignac number, because none of the positive numbers 2^k-21211012123 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211012097 and 21211012106.

It is not an unprimeable number, because it can be changed into a prime (21211912123) 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, 206103 + ... + 291376.

It is an arithmetic number, because the mean of its divisors is an integer number (3030648160).

Almost surely, 2^21211012123 is an apocalyptic number.

21211012123 is a deficient number, since it is larger than the sum of its proper divisors (3034173157).

21211012123 is an equidigital number, since it uses as much as digits as its factorization.

21211012123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 503577.

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

Adding to 21211012123 its reverse (32121011212), we get a palindrome (53332023335).

The spelling of 21211012123 in words is "twenty-one billion, two hundred eleven million, twelve thousand, one hundred twenty-three".