21001032123 has 16 divisors (see below), whose sum is σ = 28498176000. Its totient is φ = 13752658400.

The previous prime is 21001032113. The next prime is 21001032149. The reversal of 21001032123 is 32123010012.

It is a cyclic number.

It is not a de Polignac number, because 21001032123 - 2⁸ = 21001031867 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21001032103) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184678 + ... + 275876.

It is an arithmetic number, because the mean of its divisors is an integer number (1781136000).

Almost surely, 2^21001032123 is an apocalyptic number.

21001032123 is a deficient number, since it is larger than the sum of its proper divisors (7497143877).

21001032123 is a wasteful number, since it uses less digits than its factorization.

21001032123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92562.

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

Adding to 21001032123 its reverse (32123010012), we get a palindrome (53124042135).

The spelling of 21001032123 in words is "twenty-one billion, one million, thirty-two thousand, one hundred twenty-three".