21021322123 has 8 divisors (see below), whose sum is σ = 21175212960. Its totient is φ = 20867982720.

The previous prime is 21021322111. The next prime is 21021322129. The reversal of 21021322123 is 32122312012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021322123 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21021322123.

It is not an unprimeable number, because it can be changed into a prime (21021322129) 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, 61183 + ... + 213976.

It is an arithmetic number, because the mean of its divisors is an integer number (2646901620).

Almost surely, 2^21021322123 is an apocalyptic number.

21021322123 is a deficient number, since it is larger than the sum of its proper divisors (153890837).

21021322123 is a wasteful number, since it uses less digits than its factorization.

21021322123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275717.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21021322123 its reverse (32122312012), we get a palindrome (53143634135).

The spelling of 21021322123 in words is "twenty-one billion, twenty-one million, three hundred twenty-two thousand, one hundred twenty-three".