21031020123 has 8 divisors (see below), whose sum is σ = 28188174336. Its totient is φ = 13947273000.

The previous prime is 21031020119. The next prime is 21031020239. The reversal of 21031020123 is 32102013012.

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

It is not a de Polignac number, because 21031020123 - 2² = 21031020119 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21031020323) 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, 18351103 + ... + 18352248.

It is an arithmetic number, because the mean of its divisors is an integer number (3523521792).

Almost surely, 2^21031020123 is an apocalyptic number.

21031020123 is a deficient number, since it is larger than the sum of its proper divisors (7157154213).

21031020123 is a wasteful number, since it uses less digits than its factorization.

21031020123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36703545.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21031020123 its reverse (32102013012), we get a palindrome (53133033135).

The spelling of 21031020123 in words is "twenty-one billion, thirty-one million, twenty thousand, one hundred twenty-three".