21231024021 has 16 divisors (see below), whose sum is σ = 31457272320. Its totient is φ = 14152259520.

The previous prime is 21231024013. The next prime is 21231024029. The reversal of 21231024021 is 12042013212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21231024013) and next prime (21231024029).

It is not a de Polignac number, because 21231024021 - 2³ = 21231024013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21231023985 and 21231024003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231024029) 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, 194941 + ... + 283661.

It is an arithmetic number, because the mean of its divisors is an integer number (1966079520).

Almost surely, 2^21231024021 is an apocalyptic number.

It is an amenable number.

21231024021 is a deficient number, since it is larger than the sum of its proper divisors (10226248299).

21231024021 is an equidigital number, since it uses as much as digits as its factorization.

21231024021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97593 (or 97587 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21231024021 its reverse (12042013212), we get a palindrome (33273037233).

The spelling of 21231024021 in words is "twenty-one billion, two hundred thirty-one million, twenty-four thousand, twenty-one".