20231221021 has 8 divisors (see below), whose sum is σ = 22432233888. Its totient is φ = 18090510000.

The previous prime is 20231221013. The next prime is 20231221027. The reversal of 20231221021 is 12012213202.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20231221021 - 2³ = 20231221013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20231220986 and 20231221004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20231221027) 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, 15074755 + ... + 15076096.

It is an arithmetic number, because the mean of its divisors is an integer number (2804029236).

Almost surely, 2^20231221021 is an apocalyptic number.

It is an amenable number.

20231221021 is a deficient number, since it is larger than the sum of its proper divisors (2201012867).

20231221021 is a wasteful number, since it uses less digits than its factorization.

20231221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30150923.

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

Adding to 20231221021 its reverse (12012213202), we get a palindrome (32243434223).

The spelling of 20231221021 in words is "twenty billion, two hundred thirty-one million, two hundred twenty-one thousand, twenty-one".