21023001021 has 32 divisors (see below), whose sum is σ = 31365671040. Its totient is φ = 12417235200.

The previous prime is 21023001017. The next prime is 21023001047. The reversal of 21023001021 is 12010032012.

It is not a de Polignac number, because 21023001021 - 2² = 21023001017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21023000988 and 21023001006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023001071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 171511 + ... + 267323.

It is an arithmetic number, because the mean of its divisors is an integer number (980177220).

Almost surely, 2^21023001021 is an apocalyptic number.

It is an amenable number.

21023001021 is a deficient number, since it is larger than the sum of its proper divisors (10342670019).

21023001021 is a wasteful number, since it uses less digits than its factorization.

21023001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95997.

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21023001021 its reverse (12010032012), we get a palindrome (33033033033).

The spelling of 21023001021 in words is "twenty-one billion, twenty-three million, one thousand, twenty-one".