20221220021 has 8 divisors (see below), whose sum is σ = 20921791800. Its totient is φ = 19520867520.

The previous prime is 20221219979. The next prime is 20221220023. The reversal of 20221220021 is 12002212202.

It can be written as a sum of positive squares in 4 ways, for example, as 757900900 + 19463319121 = 27530^2 + 139511^2 .

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 20221220021 - 2¹⁸ = 20220957877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20221219978 and 20221220005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20221220023) 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, 145235 + ... + 248063.

It is an arithmetic number, because the mean of its divisors is an integer number (2615223975).

Almost surely, 2^20221220021 is an apocalyptic number.

It is an amenable number.

20221220021 is a deficient number, since it is larger than the sum of its proper divisors (700571779).

20221220021 is a wasteful number, since it uses less digits than its factorization.

20221220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109639.

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 20221220021 its reverse (12002212202), we get a palindrome (32223432223).

The spelling of 20221220021 in words is "twenty billion, two hundred twenty-one million, two hundred twenty thousand, twenty-one".