20213231221 has 8 divisors (see below), whose sum is σ = 20425983840. Its totient is φ = 20000920368.

The previous prime is 20213231179. The next prime is 20213231231. The reversal of 20213231221 is 12213231202.

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 20213231221 - 2¹³ = 20213223029 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20213231231) 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, 18046 + ... + 201871.

It is an arithmetic number, because the mean of its divisors is an integer number (2553247980).

Almost surely, 2^20213231221 is an apocalyptic number.

It is an amenable number.

20213231221 is a deficient number, since it is larger than the sum of its proper divisors (212752619).

20213231221 is a wasteful number, since it uses less digits than its factorization.

20213231221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220883.

The product of its (nonzero) digits is 288, while the sum is 19.

Subtracting from 20213231221 its sum of digits (19), we obtain a palindrome (20213231202).

Adding to 20213231221 its reverse (12213231202), we get a palindrome (32426462423).

The spelling of 20213231221 in words is "twenty billion, two hundred thirteen million, two hundred thirty-one thousand, two hundred twenty-one".