21031024021 has 4 divisors (see below), whose sum is σ = 24035456032. Its totient is φ = 18026592012.

The previous prime is 21031024013. The next prime is 21031024033. The reversal of 21031024021 is 12042013012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21031024021 - 2³ = 21031024013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21031023986 and 21031024004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031024121) 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, 1502215995 + ... + 1502216008.

It is an arithmetic number, because the mean of its divisors is an integer number (6008864008).

Almost surely, 2^21031024021 is an apocalyptic number.

It is an amenable number.

21031024021 is a deficient number, since it is larger than the sum of its proper divisors (3004432011).

21031024021 is an equidigital number, since it uses as much as digits as its factorization.

21031024021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3004432010.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21031024021 its reverse (12042013012), we get a palindrome (33073037033).

The spelling of 21031024021 in words is "twenty-one billion, thirty-one million, twenty-four thousand, twenty-one".