20213121 has 4 divisors (see below), whose sum is σ = 26950832. Its totient is φ = 13475412.

The previous prime is 20213107. The next prime is 20213183. The reversal of 20213121 is 12131202.

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 not a de Polignac number, because 20213121 - 2¹⁰ = 20212097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20213097 and 20213106.

It is not an unprimeable number, because it can be changed into a prime (20283121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3368851 + ... + 3368856.

It is an arithmetic number, because the mean of its divisors is an integer number (6737708).

Almost surely, 2^20213121 is an apocalyptic number.

It is an amenable number.

20213121 is a deficient number, since it is larger than the sum of its proper divisors (6737711).

20213121 is an equidigital number, since it uses as much as digits as its factorization.

20213121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6737710.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 20213121 is about 4495.9004659801. The cubic root of 20213121 is about 272.4025227200.

Adding to 20213121 its reverse (12131202), we get a palindrome (32344323).

The spelling of 20213121 in words is "twenty million, two hundred thirteen thousand, one hundred twenty-one".