21031033123 has 4 divisors (see below), whose sum is σ = 21033091008. Its totient is φ = 21028975240.

The previous prime is 21031033117. The next prime is 21031033147. The reversal of 21031033123 is 32133013012.

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 21031033123 - 2⁵ = 21031033091 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 21031033123.

It is not an unprimeable number, because it can be changed into a prime (21031033193) 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, 1013536 + ... + 1034077.

It is an arithmetic number, because the mean of its divisors is an integer number (5258272752).

Almost surely, 2^21031033123 is an apocalyptic number.

21031033123 is a deficient number, since it is larger than the sum of its proper divisors (2057885).

21031033123 is a wasteful number, since it uses less digits than its factorization.

21031033123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2057884.

The product of its (nonzero) digits is 324, while the sum is 19.

Adding to 21031033123 its reverse (32133013012), we get a palindrome (53164046135).

The spelling of 21031033123 in words is "twenty-one billion, thirty-one million, thirty-three thousand, one hundred twenty-three".